RESUMO
PURPOSE: To understand the natural history and clinical outcomes for patients with X-linked agammaglobulinemia (XLA) in the United States utilizing the United States Immunodeficiency Network (USIDNET) patient registry. METHODS: The USIDNET registry was queried for data from XLA patients collected from 1981 to 2019. Data fields included demographics, clinical features before and after diagnosis of XLA, family history, genetic mutation in Bruton's tyrosine kinase (BTK), laboratory findings, treatment modalities, and mortality. RESULTS: Data compiled through the USIDNET registry on 240 patients were analyzed. Patient year of birth ranged from 1945 to 2017. Living status was available for 178 patients; 158/178 (88.8%) were alive. Race was reported for 204 patients as follows: White, 148 (72.5%); Black/African American, 23 (11.2%); Hispanic, 20 (9.8%); Asian or Pacific Islander, 6 (2.9%), and other or more than one race, 7 (3.4%). The median age at last entry, age at disease onset, age at diagnosis, and length of time with XLA diagnosis was 15 [range (r) = 1-52 years], 0.8 [r = birth-22.3 years], 2 [r = birth-29 years], and 10 [r = 1-56 years] years respectively. One hundred and forty-one patients (58.7%) were < 18 years of age. Two hundred and twenty-one (92%) patients were receiving IgG replacement (IgGR), 58 (24%) were on prophylactic antibiotics, and 19 (7.9%) were on immunomodulatory drugs. Eighty-six (35.9%) patients had undergone surgical procedures, two had undergone hematopoietic cell transplantation, and two required liver transplantation. The respiratory tract was the most affected organ system (51.2% of patients) followed by gastrointestinal (40%), neurological (35.4%), and musculoskeletal (28.3%). Infections were common both before and after diagnosis, despite IgGR therapy. Bacteremia/sepsis and meningitis were reported more frequently before XLA diagnosis while encephalitis was more commonly reported after diagnosis. Twenty patients had died (11.2%). The median age of death was 21 years (range = 3-56.7 years). Neurologic condition was the most common underlying co-morbidity for those XLA patients who died. CONCLUSIONS: Current therapies for XLA patients reduce early mortality, but patients continue to experience complications that impact organ function. With improved life expectancy, more efforts will be required to improve post-diagnosis organ dysfunction and quality of life. Neurologic manifestations are an important co-morbidity associated with mortality and not yet clearly fully understood.
Assuntos
Agamaglobulinemia , Doenças Genéticas Ligadas ao Cromossomo X , Humanos , Lactente , Pré-Escolar , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Qualidade de Vida , Tirosina Quinase da Agamaglobulinemia/genética , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Agamaglobulinemia/diagnóstico , Agamaglobulinemia/epidemiologia , Agamaglobulinemia/terapia , Mutação/genéticaRESUMO
INTRODUCTION: Liver Glycogen Storage Disease Type IX (GSD IX) is one of the most common forms of GSD. It is caused by a deficiency in enzyme phosphorylase kinase (PhK), a complex, hetero-tetrameric enzyme comprised of four subunits - α, ß, γ, and δ - each with tissue specific isoforms encoded by different genes. Until the recent availability of gene panels and exome sequencing, the diagnosis of liver GSD IX did not allow for differentiation of these subtypes. This study presents the first comprehensive literature review for liver GSD IX subtypes - GSD IX α2, ß, and γ2. We aim to better characterize the natural history of liver GSD IX and further investigate if there are subtype-specific differences in clinical presentation. METHODS: A comprehensive literature review was performed with the help of a medical librarian at Duke University Medical Center to gather all published patients of liver GSD IX. Our refined search yielded 74 articles total. Available patient data were compiled into an excel spreadsheet. Data were analyzed via descriptive statistics. The number of patients with specific symptoms were individually summed and reported as a percentage of the total number of patients for which data were available or were averaged and reported as a mean numerical value. Published pathology reports were scored using the International Association of the Study of the Liver Scale. RESULTS: There were a total of 183 GSD IX α2 patients, 17 GSD IX ß patients, and 30 GSD IX γ2 patients. Average age at diagnosis was 4 years for GSD IX α2 patients, 2.34 years for GSD IX ß patients, and 1.81 years for GSD IX γ2 patients. Hepatomegaly was reported in 164/176 (93.2%) of GSD IX α2 patients, 16/17 (94.1%) of GSD IX ß patients, and 30/30 (100%) of GSD IX γ2 patients. Fasting hypoglycemia was reported in 53/121 (43.8%) of GSD IX α2 patients, 8/16 (50%) of GSD IX ß patients, and 18/19 (94.7%) of GSD IX γ2 patients. Liver biopsy pathology reports were available and interpreted for 46 GSD IX α2 patients, 3 GSD IX ß patients, and 24 GSD IX γ2 patients. 22/46 (47.8%) GSD IX α2 patients, 1/3 (33.3%) GSD IX ß patients, and 23/24 (95.8%) GSD IX γ2 patients with available pathology reports documented either some degree of fibrosis or cirrhosis. CONCLUSION: Our comprehensive review demonstrates quantitatively that the clinical presentation of GSD IX γ2 patients is more severe than that of GSD IX α2 or ß patients. However, our study also shows the existence of a severe phenotype in GSD IX α2, evidenced by early onset liver pathology in conjunction with clinical symptoms. There is need for a more robust natural history study to better understand the variability in liver pathophysiology within liver GSD IX; in addition, further study of mutations and gene mapping could bring a better understanding of the relationship between genotype and clinical presentation.
Assuntos
Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doença de Depósito de Glicogênio/epidemiologia , Fosforilase Quinase/genética , Pré-Escolar , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Genótipo , Doença de Depósito de Glicogênio/diagnóstico , Doença de Depósito de Glicogênio/genética , Doença de Depósito de Glicogênio/metabolismo , Humanos , Lactente , Fígado/metabolismo , Fígado/patologia , Masculino , Mutação/genética , Subunidades Proteicas/genéticaRESUMO
Background: X-linked agammaglobulinemia (XLA) is caused by a mutation of the Bruton's tyrosine kinase (BTK) gene and is the most common genetic mutation in patients with congenital agammaglobulinemia. The aim of this study was to analyze the clinical features, genetic defects, and/or BTK expression in patients suspected of having XLA who were referred from the Taiwan Foundation of Rare Disorders (TFRD). Methods: Patients with recurrent bacterial infections in the first 2 years of life, serum IgG/A/M below 2 standard deviations of the normal range, and â¦2% CD19+B cells were enrolled during the period of 2004-2019. The frequency of infections, pathogens, B-lymphocyte subsets, and family pedigree were recorded. Peripheral blood samples were sent to our institute for BTK expression and genetic analysis. Results: Nineteen (from 16 families) out of 29 patients had BTK mutations, including 7 missense mutations, 7 splicing mutations, 1 nonsense mutation, 2 huge deletions, and 2 nucleotide deletions. Six novel mutations were detected: c.504G>T [p.K168N], c.895-2A>G [p.Del K290 fs 23*], c.910T>G [p.F304V], c.1132T>C [p.T334H], c.1562A>T [p.D521V], and c.1957delG [Del p.D653 fs plus 45 a.a.]. All patients with BTK mutations had obviously decreased BTK expressions. Pseudomonas sepsis developed in 14 patients and led to both Shanghai fever and recurrent hemophagocytic lymphohistiocytosis (HLH). Recurrent sinopulmonary infections and bronchiectasis occurred in 11 patients. One patient died of pseudomonas sepsis and another died of hepatocellular carcinoma before receiving optimal treatment. Two patients with contiguous gene deletion syndrome (CGS) encompassing the TIMM8A/DDP1 gene presented with early-onset progressive post-lingual sensorineural Deafness, gradual Dystonia, and Optic Neuronopathy syndrome (DDON) or Mohr-Tranebjaerg syndrome (MTS). Conclusion: Pseudomonas sepsis was more common (74%) than recurrent sinopulmonary infections in Taiwanese XLA patients, and related to Shanghai fever and recurrent HLH, both of which were prevented by regular immunoglobulin infusions. Approximately 10% of patients belonged to CGS involving the TIMM8A/DDP1 gene and presented with the DDON/MTS phenotype in need of aggressive psychomotor therapy.
Assuntos
Tirosina Quinase da Agamaglobulinemia/genética , Agamaglobulinemia/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Mutação/genética , Pseudomonas/fisiologia , Infecções Respiratórias/epidemiologia , Sepse/genética , Adolescente , Adulto , Agamaglobulinemia/epidemiologia , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Estudos de Associação Genética , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Humanos , Lactente , Masculino , Proteínas de Membrana Transportadoras/genética , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial , Linhagem , Fenótipo , Infecções Respiratórias/imunologia , Sepse/epidemiologia , Taiwan/epidemiologia , Adulto JovemRESUMO
BACKGROUND: X-linked agammaglobulinemia (XLA) is the prototype of primary humoral immunodeficiencies. Long-term follow-up studies regarding disease-related complications and outcome are scarce. OBJECTIVE: Our aim was to describe the natural history of XLA. METHODS: A nationwide multicenter study based on the Italian Primary Immunodeficiency Network registry was established in 2000 in Italy. Affected patients were enrolled by documenting centers, and the patients' laboratory, clinical, and imaging data were recorded on an annual base. RESULTS: Data on the patients (N = 168) were derived from a cumulative follow-up of 1370 patient-years, with a mean follow-up of 8.35 years per patient. The mean age at diagnosis decreased after establishment of the Italian Primary Immunodeficiency Network registry (84 months before vs 23 months after). Respiratory, skin, and gastrointestinal manifestations were the most frequent clinical symptoms at diagnosis and during long-term follow-up. Regular immunoglobulin replacement treatment reduced the incidence of invasive infections. Affected patients developed chronic lung disease over time (47% after 40 years of follow-up) in the presence of chronic sinusitis (84%). Malignancies were documented in a minority of cases (3.7%). Overall survival for affected patients was significantly reduced when compared with that for the healthy male Italian population, and it further deteriorated in the presence of chronic lung disease. CONCLUSIONS: This is the first detailed long-term follow-up study for patients with XLA, revealing that although immunoglobulin replacement treatment reduces the incidence of invasive infections, it does not appear to influence the development of chronic lung disease. The overall survival of affected patients is reduced. Further studies are warranted to improve patients' clinical management and increase awareness among physicians.
Assuntos
Agamaglobulinemia/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Infecções/epidemiologia , Pneumopatias/epidemiologia , Sinusite/epidemiologia , Adolescente , Adulto , Agamaglobulinemia/mortalidade , Criança , Pré-Escolar , Seguimentos , Doenças Genéticas Ligadas ao Cromossomo X/mortalidade , Humanos , Lactente , Recém-Nascido , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Análise de Sobrevida , Adulto JovemRESUMO
BACKGROUND: Congenital agammaglobulinemia is the first primary immunodeficiency disorder characterized by a defect in B lymphocyte development and subsequently decreased immunoglobulin levels. These patients are prone to suffer from recurrent infections mostly involving the respiratory tract. In this study, we aimed to describe in detail respiratory tract complications as the most prominent clinical feature among agammaglobulinemic patients. METHODS: A total number of 115 patients were included. Demographic, clinical, and genetic data were collected from the patients' medical records. Among the available patients, pulmonary function tests (PFTs) and/or high-resolution computed tomography (HRCT) were performed. RESULTS: Respiratory tract complications (85.2%) especially pneumonia (62.6%) were the most prominent clinical features in our cohort. Among patients with abnormal PFT results (N = 19), a mixed respiratory pattern was observed in 36.8%. HRCT was carried out in 29 patients; Bhalla scoring-based evaluation of these patients indicated excellent (44.8%), followed by good (34.5%) and mild (20.7%) results. Bronchiectasis was found in 13 patients undergoing HRCT (44.8%). We found significant inverse correlations between the Bhalla score and incidence rate of pneumonia, as well as the presence of bronchiectasis. Patients with abnormal PFT results had statistically significant higher bronchiectasis frequency and lower Bhalla scores compared to those with normal results. Forty-one patients were deceased, and here, respiratory failure was the most common cause of death (45.5%). CONCLUSION: High prevalence of respiratory tract infections among agammaglobulinemic patients and subsequent progression to permanent lung damage highlights the importance of implementing respiratory evaluation as part of routine follow-up program of agammaglobulinemic patients. Physicians should be aware of this and regularly monitor the respiratory function of these patients to allow for timely diagnosis and treatment initiation aiming to improve patients' prognosis and quality of life.
Assuntos
Agamaglobulinemia/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Infecções Respiratórias/epidemiologia , Adolescente , Agamaglobulinemia/complicações , Bronquiectasia/epidemiologia , Bronquiectasia/etiologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/complicações , Humanos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Masculino , Pneumonia/epidemiologia , Pneumonia/etiologia , Prevalência , Qualidade de Vida , Testes de Função Respiratória , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/etiologia , Estudos Retrospectivos , Inquéritos e Questionários , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
X-linked lymphoproliferative syndrome (XLP) is a rare primary immunodeficiency disease that can be divided into two types: SAP deficiency (XLP1) and XIAP deficiency (XLP2), caused by mutations in the SH2D1A and XIAP genes, respectively. Few cases of XLP (particularly XIAP deficiency) have been reported in mainland China; hence, little is known about the characteristics of Chinese patients with XLP. We identified 13 and 7 patients with SAP and XIAP deficiency, respectively, in our center. Of our 20 patients, 19/20 (95%) presented with disease symptoms at a very early age: six in infancy and 13 in childhood. One XIAP- and three SAP-deficient patients died, while 3/7(42.9%) and 4/13(30.8%), respectively, developed hemophagocytic lymphohistiocytosis (HLH). Epstein-Barr virus (EBV) infection was significantly more common in SAP-deficient 10/13 (76.9%) than XIAP-deficient 2/7 (28.6%) patients, as was hypogammaglobulinemia (10/13 (76.9%) vs. 1/7 (14.3%)). None of the seven XIAP-deficient patients had colitis or lymphoma. Nine SAP-deficient patients and five XIAP-deficient patients showed markedly deficient SAP and XIAP expression, respectively, in lymphocytes. Significantly reduced levels of switched memory B cells were observed in six SAP-deficient patients with persistent hypogammaglobulinemia. One of 13 (7.7%) SAP-deficient patients and 1 of 7 (12.3%) XIAP-deficient patients have received HSCT treatment and are now alive and well; the other alive patients were waiting for HSCT. We also summarized clinical, genetic, and immunological characteristics of all 55 patients (including our 20 patients) reported in the literature in mainland China today.Conclusion: The overall characteristics of SAP deficiency in mainland China were consistent with those in previous reports, whereas manifestations of XIAP deficiency varied significantly. None of inflammatory bowel disease (IBD) has been reported among XIAP-deficient patients in our center; however, whether Chinese XIAP-deficient patients will develop colitis in the future warrants further investigation. HSCT is the only curative therapy for XLP and this therapy should be urgently considered.What is Known:⢠SAP and XIAP deficiencies share common clinical feature, HLH, whereas they also have their own specific manifestations.⢠IBD affects 25-30% of XIAP-deficient patients, which has been reported in other countries especially in European country and Japan.What is New:⢠This is the largest patient cohort study of XLP in China.⢠We firstly summarized the clinical features and outcomes of Chinese XIAP-deficient patients and found only 1 in 22 patients developed IBD and diet background may contribute to it; Asian SAP-deficient patients carrying SH2D1A R55X mutation were more prone to HLH.
Assuntos
Causas de Morte , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Predisposição Genética para Doença/epidemiologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Transtornos Linfoproliferativos/epidemiologia , Transtornos Linfoproliferativos/genética , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/genética , Adolescente , Criança , Pré-Escolar , China , Estudos de Coortes , Análise Mutacional de DNA , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/cirurgia , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Lactente , Transtornos Linfoproliferativos/diagnóstico , Transtornos Linfoproliferativos/cirurgia , Masculino , Linhagem , Estudos Retrospectivos , Medição de Risco , Análise de SobrevidaRESUMO
Las agammaglobulinemias primarias (AP) resultan de alteraciones específicas en las células B, lo cual, conduce a baja producción de anticuerpos. La sospecha diagnóstica se establece con el antecedente de infecciones a repetición, inmunoglobulinas bajas y la ausencia linfocitos B CD19+. El diagnóstico se confirma mediante el análisis genético y la detección de una mutación ligada en el cromosoma X o autosómico recesiva o dominante. En Perú, no hay literatura sobre AP ni reportes sobre el genotipo de los pacientes con sospecha de AP. Bajo este escenario, se realizó un estudio que describió el genotipo de pacientes con sospecha de AP. Se encontraron 20 pacientes con mutaciones en el gen BTK y una mutación autosómica recesiva IGHM. Se hallaron 13 mutaciones hereditarias y siete mutaciones de novo. Se concluye que las AP son, en su mayoría, mutaciones en el gen BTK que corresponden con AP ligadas al cromosoma X.
Primary agammaglobulinemia result from specific alterations in B cells, which lead to low antibody production. Diagnostic suspicion is established with a history of repeated infections, low immunoglobulins, and absence of CD19+ B lymphocytes. The diagnosis is confirmed by genetic analysis and the detection of a mutation linked to the X or autosomal recessive or dominant chromosome. In Peru, there is no literature on primary agammaglobulinemia and no reports on the genotype of patients with suspected primary agammaglobulinemia. Under this scenario, a study was performed to describe the genotype of patients with suspected primary agammaglobulinemia. Twenty (20) patients were found with mutations in the BTK gene and an autosomal recessive IGHM mutation. Thirteen (13) hereditary mutations and seven de novo mutations were found. It is concluded that the group of primary agammaglobulinemia are mostly mutations in the BTK gene, corresponding to X-linked agammaglobulinemia.
Assuntos
Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Adulto Jovem , Cadeias mu de Imunoglobulina/genética , Agamaglobulinemia/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Tirosina Quinase da Agamaglobulinemia/genética , Doença das Cadeias Pesadas/genética , Peru/epidemiologia , Agamaglobulinemia/diagnóstico , Agamaglobulinemia/genética , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/genética , MutaçãoRESUMO
BACKGROUND: X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases. OBJECTIVE: Due to the low prevalence of XLH, an experts' opinion survey was conducted across Italian centers to collect data on XLH and on its management. METHODS: A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy. RESULTS: Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5 years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients. CONCLUSIONS: XLH remains a severe condition with significant morbidities.
Assuntos
Raquitismo Hipofosfatêmico Familiar/genética , Doenças Genéticas Ligadas ao Cromossomo X , Padrões de Prática Médica/estatística & dados numéricos , Adolescente , Adulto , Criança , Pré-Escolar , Raquitismo Hipofosfatêmico Familiar/diagnóstico , Raquitismo Hipofosfatêmico Familiar/epidemiologia , Raquitismo Hipofosfatêmico Familiar/terapia , Feminino , Fator de Crescimento de Fibroblastos 23 , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/terapia , Humanos , Lactente , Recém-Nascido , Itália/epidemiologia , Masculino , Inquéritos e QuestionáriosRESUMO
Overgrowth syndromes are a heterogeneous group of rare disorders characterized by generalized or segmental excessive growth commonly associated with additional features, such as visceromegaly, macrocephaly and a large range of various symptoms. These syndromes are caused by either genetic or epigenetic anomalies affecting factors involved in cell proliferation and/or the regulation of epigenetic markers. Some of these conditions are associated with neurological anomalies, such as cognitive impairment or autism. Overgrowth syndromes are frequently associated with an increased risk of cancer (embryonic tumours during infancy or carcinomas during adulthood), but with a highly variable prevalence. Given this risk, syndrome-specific tumour screening protocols have recently been established for some of these conditions. Certain specific clinical traits make it possible to discriminate between different syndromes and orient molecular explorations to determine which molecular tests to conduct, despite the syndromes having overlapping clinical features. Recent advances in molecular techniques using next-generation sequencing approaches have increased the number of patients with an identified molecular defect (especially patients with segmental overgrowth). This Review discusses the clinical and molecular diagnosis, tumour risk and recommendations for tumour screening for the most prevalent generalized and segmental overgrowth syndromes.
Assuntos
Neoplasias/epidemiologia , Neoplasias/genética , Arritmias Cardíacas/epidemiologia , Arritmias Cardíacas/genética , Arritmias Cardíacas/patologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Gigantismo/epidemiologia , Gigantismo/genética , Gigantismo/patologia , Cardiopatias Congênitas/epidemiologia , Cardiopatias Congênitas/genética , Cardiopatias Congênitas/patologia , Humanos , Deficiência Intelectual/epidemiologia , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Megalencefalia/epidemiologia , Megalencefalia/genética , Megalencefalia/patologia , Neoplasias/patologia , Gravidez , Fatores de Risco , Síndrome de Sotos/epidemiologia , Síndrome de Sotos/genética , Síndrome de Sotos/patologia , SíndromeRESUMO
Sideroblastic anemias are heterogeneous rare hematological disorders, representing diverse phenotypes. In this study, the genetic cause of congenital, transfusion dependent anemia in four unrelated families consisting of eighteen individuals, with one affected member was investigated. Probands were suspected to rare anemias, including sideroblastic anemia. Whole exome sequencing in probands followed by segregation analysis in families was performed. Two novel frame shift mutations and one previously reported missense mutation in SLC25A38 gene was identified in these families. Mutations and their recessive mood of inheritance in each family were confirmed by PCR and Sanger sequencing. These findings suggest that sideroblastic anemia must be considered a possible etiology in cases with unexplained hemolytic anemia. Furthermore, mutations in SLC25A38 gene could be a prevalent cause of congenital sideroblastic anemia (CSA) in the Iranian population. Considering that parents of all affected individuals had consanguineous marriage and belong to sub populations, where consanguineous marriage is prevalent, it is important to perform carrier screening and genetic counseling in these families and their close relatives as prevention strategy in populations at risk.
Assuntos
Anemia Sideroblástica/genética , Genes Mitocondriais , Doenças Genéticas Ligadas ao Cromossomo X/genética , Heterozigoto , Proteínas de Transporte da Membrana Mitocondrial/genética , Mutação , Idade de Início , Alelos , Anemia Sideroblástica/diagnóstico , Anemia Sideroblástica/epidemiologia , Medula Óssea/patologia , Criança , Pré-Escolar , Consanguinidade , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Genótipo , Humanos , Lactente , Irã (Geográfico)/epidemiologia , Masculino , Mutação de Sentido Incorreto , Linhagem , Sequenciamento do ExomaRESUMO
BACKGROUND: Primary antibody deficiency (PAD) is the most common group of primary immunodeficiency disorders, resulting from different defects in the development and function of B cell lineage. Common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA) are two of the major types of PADs. Optimal growth and subsequently bone health could potentially compromise due to the interference of several factors in PAD with childhood onset. In the present study, our aim was to evaluate bone mineral density (BMD) of patients with CVID and XLA. METHODS: BMD of 37 CVID and 19 XLA patients was examined. Total BMD was determined by dual-energy X-ray absorptiometry and the calculated scores were compared internally and externally with age-sex matched and ethnic-specific reference. Related factors associated with bone density including immune-related complications, serum calcium, phosphate, total alkaline phosphatase, 25(OH) vitamin D and parathyroid hormone levels were recorded. RESULTS: The median age at the time of study was 20 years among all patients and was not statistically different between CVID and XLA groups and the mean of body mass index (BMI) was 19.4±4.6 kg/cm². Thirty-eight (67.9%) of total patients had normal BMD and 18 (32.1%) patients had a low BMD. BMI was positively correlated with BMD at lumbar spine and femoral neck. The number of low BMD patients in CVID (40.5%) group was more than the XLA (15.8%). CONCLUSION: Beside nutritional, gastrointestinal and infectious complications which are shared in both groups of patients, CVID patients are more prone to alteration of BMD due to association with lymphoproliferative and endocrine diseases. Therefore routine evaluation of bone density and treatment adjustment should be considered in all PAD patients particularly in CVID patients.
Assuntos
Agamaglobulinemia/diagnóstico por imagem , Agamaglobulinemia/metabolismo , Densidade Óssea/fisiologia , Imunodeficiência de Variável Comum/diagnóstico por imagem , Imunodeficiência de Variável Comum/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico por imagem , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Absorciometria de Fóton/métodos , Adolescente , Adulto , Agamaglobulinemia/epidemiologia , Criança , Imunodeficiência de Variável Comum/epidemiologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Humanos , Masculino , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Primary immunodeficiencies (PID) are characterized by alteration of the components of the immune system. Humoral deficiencies represent 50%. The most common are selective IgA deficiency, Bruton agammaglobulinemia, and common variable immunodeficiency (CVID). OBJECTIVE: To describe the epidemiological and clinical characteristics of adults with humoral PID, cared for in a Primary Humoral Immunodeficiencies Clinic. METHODS: A descriptive cross-sectional study that included a year of analysis, including 35 patients with humoral PID, 31 with CVID, and 4 with Bruton agammaglobulinemia. Data were analyzed with descriptive statistics. RESULTS: Of 35 patients studied, 31 had CVID (88.5%) and 4 (11.5%) Bruton agammaglobulinemia; 21 were men and 14 women. The age at onset of symptoms was 22.7 years, and the delay in diagnosis was 7.2 years. 11.4% of CVID patients died during the study; 4 had malignancies, 22.8% autoimmune diseases, and 48.5% gastrointestinal disorders. Patients with Bruton agammaglobulinemia presented no comorbidities. CONCLUSIONS: Unlike reports in the literature, in the study group, CVID was the most common cause of humoral PID, predominantly in men; the most common gastrointestinal disorder was intestinal functional disorder.
Antecedentes: Las inmunodeficiencias primarias (IDP) son trastornos de los componentes del sistema inmune. Las deficiencias humorales representan el 50%. Las más comunes son el déficit selectivo de IgA, agammaglobulinemia de Bruton y la inmunodeficiencia común variable (IDCV). Objetivo: Describir las características epidemiológicas y clínicas de adultos con IDP humorales, atendidos en una Clínica de Inmunodeficiencias Primarias Humorales. Métodos: Estudio descriptivo trasversal que abarcó un año de análisis, en el que se incluyeron 35 pacientes con IDP humoral. Los datos se analizaron con estadística descriptiva. Resultados: De 35 pacientes estudiados, 31 tuvieron IDCV (88.5%) y 4 (11.5%) agammaglobulinemia de Bruton; 21 fueron hombres y 14 mujeres. La edad al inicio de los síntomas fue de 22.7 años y el tiempo de retraso en el diagnóstico fue de 7.2 años; 11.4% de los pacientes con IDCV fallecieron durante el estudio; 4 padecieron neoplasias, 22.8% enfermedades autoinmunes y 48.5% alteraciones gastrointestinales. Los pacientes con agammaglobulinemia de Bruton no presentaron comorbilidades. Conclusiones: A diferencia de lo informado en la literatura, la IDCV fue la causa más común de IDP humoral en el grupo estudiado, con predominio en hombres; la alteración gastrointestinal más común fue el trastorno funcional intestinal.
Assuntos
Agamaglobulinemia/epidemiologia , Imunodeficiência de Variável Comum/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Adulto , Idade de Início , Estudos Transversais , Feminino , Humanos , Masculino , Fatores Sexuais , Centros de Atenção Terciária/estatística & dados numéricos , Adulto JovemRESUMO
Objectives: To present descriptive epidemiology of Orofacial Clefts and to determine the association of syndromic forms with antenatal high-risk conditions, preterm birth, and comorbidities among nested-series of cases. Methods: A study of nested-series of cases was conducted. Frequencies of cleft type, associated congenital anomalies, syndromic, non-syndromic and multiple malformation forms, and distribution of Orofacial Clefts according to sex and affected-side were determined. Odds ratios were calculated as measures of association between syndromic forms and antenatal high-risk conditions, preterm birth and comorbidities. A total of three hundred and eleven patients with Orofacial Clefts were assessed in a 12-month period. Results: The most frequent type of Orofacial Clefts was cleft lip and palate, this type of cleft was more frequent in males, whereas cleft palate occurred more often in females. The most common cases occurred as non-syndromic forms. Aarskog-Scott syndrome showed the highest frequency amongst syndromic forms. Hypertensive disorders in pregnancy, developmental dysplasia of the hip, central nervous diseases and respiratory failure showed significant statistical associations (p <0.05) with syndromic forms. Conclusions: These data provide an epidemiological reference of Orofacial Clefts in Colombia. Novel associations between syndromic forms and clinical variables are determined. In order to investigate causality relationships between these variables further studies must be carried out.
Objetivos: Presentar la epidemiología descriptiva en torno a las Fisuras Orofaciales y determinar asociaciones entre Fisuras Orofaciales sindromica y antecedentes antenatales de alto riesgo, parto pretérmino, y comorbilidades en una población Colombiana. Métodos: Se planteó un estudio de serie de casos anidado estratificado. Se calcularon frecuencias en relación al tipo de fisura desde el punto de vista anatómico, anomalías congénitas paralelas, morbilidades y forma clínica. Se analizó la distribución de las Fisuras Orofaciales de acuerdo al género y lateralidad. Se determinaron razones de disparidad entre la forma sindrómica y antecedentes antenatales de alto riesgo, parto pretérmino, y comorbilidades. Se evaluaron trecientos once pacientes que asistieron a la consulta de genética clinica durante un año. Resultados: La Fisura Labio-palatina fue el tipo más frecuente en la muestra evaluada y la más frecuente en hombres. La Fisura Palatina fué la más frecuente en mujeres, la forma clínica más común fue la no sindrómica. En la población sindrómica el Síndrome de Aarskog-Scott mostró la frecuencia más alta. Los trastornos Hipertensivos de Embarazo, la Displasia del Desarrollo de la Cadera, las enfermedades respiratorias y del sistema nervioso central mostraron una asociación estadísticamente significativa con la forma sindrómica. (p <0.05). Conclusiones: Estos datos ofrecen una referencia epidemiológica descriptiva de las Fisuras Orofaciales en Colombia. Las asociaciones encontradas entre los aspectos clínicos estudiados y la forma sindrómica, deben ser investigadas en próximos estudios con el fin de determinar relaciones de causalidad.
Assuntos
Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fenda Labial/epidemiologia , Fissura Palatina/epidemiologia , Distribuição por Idade , Colômbia/epidemiologia , Nanismo/epidemiologia , Face/anormalidades , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Genitália Masculina/anormalidades , Deformidades Congênitas da Mão/epidemiologia , Cardiopatias Congênitas/epidemiologia , Distribuição por Sexo , SíndromeRESUMO
BACKGROUND: Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT) are caused by mutations of the WAS gene. The genotype-phenotype association of WAS and XLT have not been fully elucidated. Here, we established the largest database of WAS in China to further determine the potential correlation between genotype and phenotype and long-term outcome. PROCEDURES: We collected clinical data of 81 WAS/XLT patients, analyzed mutations of WAS gene at the genomic DNA and transcriptional/translational levels, and quantified three different patterns of WAS protein (WASp) expression in PBMCs by flow cytometry. RESULTS: There were 60 unique mutations identified, including 20 novel mutations and eight hotspots, from 75 unrelated families with a total of 81 affected members. Nearly all the patients with XLT had missense mutations and were WASp-positive in the peripheral cells, while only half of the patients with missense mutations exhibited the XLT phenotype and detectable WASp. In contrast, patients with nonsense mutations, deletions, insertions, and complex mutations were WASp-negative and developed the classic WAS phenotype. An equal number of patients with splice anomalies were either WASp-positive or WASp-negative. Long-term survival rates were lower in WASp-negative patients compared to WASp-positive patients. CONCLUSIONS: The clinical phenotype of classic WAS or milder XLT and long-term outcome are potentially influenced by the effect of these defects on gene transcription and translation. Patients with missense mutations allowing expression of mutated WASp and those with splice anomalies, which result in generation of multiple products, including normal WASp, present the attenuated XLT phenotype and show better prognosis.
Assuntos
Doenças Genéticas Ligadas ao Cromossomo X/genética , Mutação , Trombocitopenia/genética , Proteína da Síndrome de Wiskott-Aldrich/genética , Síndrome de Wiskott-Aldrich/genética , Idade de Início , Pré-Escolar , China/epidemiologia , Análise Mutacional de DNA , Bases de Dados Genéticas , Doenças em Gêmeos/genética , Citometria de Fluxo , Regulação da Expressão Gênica , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Genótipo , Transplante de Células-Tronco Hematopoéticas , Humanos , Lactente , Recém-Nascido , Masculino , Fenótipo , Biossíntese de Proteínas , Taxa de Sobrevida , Trombocitopenia/epidemiologia , Transcrição Gênica , Resultado do Tratamento , Síndrome de Wiskott-Aldrich/epidemiologia , Síndrome de Wiskott-Aldrich/terapia , Proteína da Síndrome de Wiskott-Aldrich/biossíntese , Proteína da Síndrome de Wiskott-Aldrich/deficiênciaRESUMO
OBJECTIVES: To present descriptive epidemiology of Orofacial Clefts and to determine the association of syndromic forms with antenatal high-risk conditions, preterm birth, and comorbidities among nested-series of cases. METHODS: A study of nested-series of cases was conducted. Frequencies of cleft type, associated congenital anomalies, syndromic, non-syndromic and multiple malformation forms, and distribution of Orofacial Clefts according to sex and affected-side were determined. Odds ratios were calculated as measures of association between syndromic forms and antenatal high-risk conditions, preterm birth and comorbidities. A total of three hundred and eleven patients with Orofacial Clefts were assessed in a 12-month period. RESULTS: The most frequent type of Orofacial Clefts was cleft lip and palate, this type of cleft was more frequent in males, whereas cleft palate occurred more often in females. The most common cases occurred as non-syndromic forms. Aarskog-Scott syndrome showed the highest frequency amongst syndromic forms. Hypertensive disorders in pregnancy, developmental dysplasia of the hip, central nervous diseases and respiratory failure showed significant statistical associations (p <0.05) with syndromic forms. CONCLUSIONS: These data provide an epidemiological reference of Orofacial Clefts in Colombia. Novel associations between syndromic forms and clinical variables are determined. In order to investigate causality relationships between these variables further studies must be carried out.
OBJETIVOS: Presentar la epidemiología descriptiva en torno a las Fisuras Orofaciales y determinar asociaciones entre Fisuras Orofaciales sindromica y antecedentes antenatales de alto riesgo, parto pretérmino, y comorbilidades en una población Colombiana. MÉTODOS: Se planteó un estudio de serie de casos anidado estratificado. Se calcularon frecuencias en relación al tipo de fisura desde el punto de vista anatómico, anomalías congénitas paralelas, morbilidades y forma clínica. Se analizó la distribución de las Fisuras Orofaciales de acuerdo al género y lateralidad. Se determinaron razones de disparidad entre la forma sindrómica y antecedentes antenatales de alto riesgo, parto pretérmino, y comorbilidades. Se evaluaron trecientos once pacientes que asistieron a la consulta de genética clinica durante un año. RESULTADOS: La Fisura Labio-palatina fue el tipo más frecuente en la muestra evaluada y la más frecuente en hombres. La Fisura Palatina fué la más frecuente en mujeres, la forma clínica más común fue la no sindrómica. En la población sindrómica el Síndrome de Aarskog-Scott mostró la frecuencia más alta. Los trastornos Hipertensivos de Embarazo, la Displasia del Desarrollo de la Cadera, las enfermedades respiratorias y del sistema nervioso central mostraron una asociación estadísticamente significativa con la forma sindrómica. (p <0.05). CONCLUSIONES: Estos datos ofrecen una referencia epidemiológica descriptiva de las Fisuras Orofaciales en Colombia. Las asociaciones encontradas entre los aspectos clínicos estudiados y la forma sindrómica, deben ser investigadas en próximos estudios con el fin de determinar relaciones de causalidad.
Assuntos
Fenda Labial/epidemiologia , Fissura Palatina/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Colômbia/epidemiologia , Nanismo/epidemiologia , Face/anormalidades , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Genitália Masculina/anormalidades , Deformidades Congênitas da Mão/epidemiologia , Cardiopatias Congênitas/epidemiologia , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Distribuição por Sexo , SíndromeRESUMO
PURPOSE: In the past, XLA was described as associated with several inflammatory conditions, but with adequate immune globulin treatment, these are presumed to have diminished. The actual prevalence is not known. METHODS: A web-based patient survey was conducted December 2011- February 2012. Respondents were recruited from the Immune Deficiency Foundation (IDF) patient database, online patient discussion forums and physician recruitment of patients. The questionnaire was developed jointly by IDF and by members of the USIDNET-XLA Disease Specific Working Group. Information regarding inflammatory conditions in patients with XLA was also obtained from the United States Immune Deficiency Network (USIDNET) Registry. RESULTS: Based on 128 unique patient survey responses, the majority of respondents (69%) reported having at least one inflammatory symptom, with 53% reporting multiple symptoms. However, only 28% had actually been formally diagnosed with an inflammatory condition. Although 20% reported painful joints and 11% reported swelling of the joints, only 7% were given a diagnosis of arthritis. Similarly, 21% reported symptoms of chronic diarrhea and 17% reported abdominal pain, however only 4% had been diagnosed with Crohn's disease. Data from the USIDNET Registry on 149 patients with XLA, revealed that 12% had pain, swelling or arthralgias, while 18% had been diagnosed with arthritis. Similarly, 7% of these patients had abdominal pain and 9% chronic diarrhea. CONCLUSIONS: Although patients with XLA are generally considered to have a low risk of autoimmune or inflammatory disease compared to other PIDD cohorts, data from this patient survey and a national registry indicate that a significant proportion of patients with XLA have symptoms that are consistent with a diagnosis of arthritis, inflammatory bowel disease or other inflammatory condition. Documented diagnoses of inflammatory diseases were less common but still increased over the general population. Additional data is required to begin implementation of careful monitoring of patients with XLA for these conditions. Early diagnosis and proper treatment may optimize clinical outcomes for these patients.
Assuntos
Agamaglobulinemia/diagnóstico , Artrite/diagnóstico , Doença de Crohn/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Inflamatórias Intestinais/diagnóstico , Adolescente , Adulto , Agamaglobulinemia/epidemiologia , Agamaglobulinemia/imunologia , Artrite/epidemiologia , Artrite/imunologia , Autoimunidade , Criança , Pré-Escolar , Doença de Crohn/epidemiologia , Doença de Crohn/imunologia , Coleta de Dados , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/imunologia , Humanos , Lactente , Inflamação/imunologia , Doenças Inflamatórias Intestinais/epidemiologia , Doenças Inflamatórias Intestinais/imunologia , Masculino , Pessoa de Meia-Idade , Prevalência , Inquéritos e Questionários , Estados Unidos , Adulto JovemRESUMO
OBJECTIVE: The principal objective of the study is to compare results from the experimental group of pregnant women suffering from thrombocytopenia in pregnancy with results from the control group of pregnant women with normal physiologic blood platelet count. SETTING: Department of Obstetrics and Gynaecology of the Tomas Bata Regional Hospital Zlín, Obstetrics and Gynaecology Clinic, Haematology and Oncology Clinic of the Palacky University Teaching Hospital and Medical School in Olomouc, Obstetrics and Gynaecology Clinic of the Ostrava Teaching Hospital. METHODOLOGY: A group of 200 pregnant women suffering from thrombocytopenia underwent thorough medical tests. The level of platelets, presence of anti-platelets agents, liver function (LFT), anti-phospholipid antibodies, complete blood count with differential, specific antibodies for hepatitis B and C, Lyme borreliosis and cytomegalovirus were determined from venous blood using the EIA, ELISA methods. RESULTS: Medical articles and books about thrombocytopenia divide the causes for thrombocytopenia as follows: 79.5% benign gestational thrombocytopenia, 16% preeclampsia, 2.5% HELLP syndrome, 1% immune thrombocytopenia, 1% HVC. The number of women who developed physiological anaemia in pregnancy and were overweight is identical in the experimental group of pregnant women suffering from thrombocytopenia and in the control group of pregnant women with normal physiologic blood platelet count, and the proportion of the different age groups in the two groups of pregnant women is also identical. CONCLUSION: 32% of pregnancies in the experimental group ended in a caesarean section, of which 13.5% in a group of 127 pregnant women suffering from mild thrombocytopenia, 17.5% in a group of 71 pregnant women suffering from moderate thrombocytopenia and 1% in a group of 2 pregnant women suffering from severe thrombocytopenia. 20.5% pregnancies in the control group ended in caesarean section.
Assuntos
Coagulação Sanguínea/fisiologia , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Complicações Hematológicas na Gravidez , Trombocitopenia/epidemiologia , Adulto , Cesárea , República Tcheca/epidemiologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/sangue , Doenças Genéticas Ligadas ao Cromossomo X/etiologia , Humanos , Incidência , Gravidez , Resultado da Gravidez , Trombocitopenia/sangue , Trombocitopenia/etiologiaRESUMO
This study represents the first epidemiological study based on the national registry of primary immunodeficiencies (PID) in Korea. Patient data were collected from 23 major hospitals. A total of 152 patients with PID (under 19 yr of age), who were observed from 2001 to 2005, have been entered in this registry. The period prevalence of PID in Korea in 2005 is 11.25 per million children. The following frequencies were found: antibody deficiencies, 53.3% (n = 81), phagocytic disorders, 28.9% (n = 44); combined immunodeficiencies, 13.2% (n = 20); and T cell deficiencies, 4.6% (n = 7). Congenital agammaglobulinemia (n = 21) and selective IgA deficiency (n = 21) were the most frequently reported antibody deficiency. Other reported deficiencies were common variable immunodeficiencies (n = 16), X-linked agammaglobulinemia (n = 15), IgG subclass deficiency (n = 4). Phagocytic disorder was mostly chronic granulomatous disease. A small number of patients with Wiskott-Aldrich syndrome, hyper-IgE syndrome, and severe combined immunodeficiency were also registered. Overall, the most common first manifestation was pneumonia. This study provides data that permit a more accurate estimation PID patients in Korea.
Assuntos
Síndromes de Imunodeficiência/epidemiologia , Adolescente , Agamaglobulinemia/congênito , Agamaglobulinemia/epidemiologia , Distribuição por Idade , Criança , Pré-Escolar , Imunodeficiência de Variável Comum/epidemiologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Humanos , Deficiência de IgA/epidemiologia , Deficiência de IgG/epidemiologia , Lactente , Recém-Nascido , Síndrome de Job/epidemiologia , Masculino , Prevalência , Sistema de Registros , República da Coreia/epidemiologia , Imunodeficiência Combinada Severa/epidemiologia , Distribuição por Sexo , Inquéritos e Questionários , Síndrome de Wiskott-Aldrich/epidemiologia , Adulto JovemRESUMO
Mitral valve prolapse is defined as abnormal bulging of the mitral valve leaflets into the left atrium during ventricular systole. Mitral valve prolapse is a common condition that is a risk factor for mitral regurgitation, congestive heart failure, arrhythmia, and endocarditis. Myxomatous degeneration is the most common cause of mitral prolapse in the United States and Europe, and progression of myxomatous mitral prolapse is the most common cause of mitral regurgitation that requires surgical treatment. Myxomatous degeneration appears to have genetic etiology. The genetics of myxomatous degeneration is complex and not fully worked out; it appears to be heterogeneous with multi-gene, multi-chromosomal autosomal dominance with incomplete penetrance. The molecular disorder of myxomatous degeneration appears to consist of a connective tissue disorder with altered extracellular matrix status and involves the action of matrix metalloproteinase, cysteine endoproteases, and tenomodulin. Treatment of mitral prolapse with regurgitation is complex, and the technological advances that are currently in development will be challenging and controversial.
Assuntos
Doenças Genéticas Ligadas ao Cromossomo X , Predisposição Genética para Doença/epidemiologia , Prolapso da Valva Mitral , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/fisiopatologia , Humanos , Prolapso da Valva Mitral/epidemiologia , Prolapso da Valva Mitral/genética , Prolapso da Valva Mitral/fisiopatologiaRESUMO
Centronuclear myopathy (CNM) is an inherited neuromuscular disorder characterised by clinical features of a congenital myopathy and centrally placed nuclei on muscle biopsy.The incidence of X-linked myotubular myopathy is estimated at 2/100000 male births but epidemiological data for other forms are not currently available.The clinical picture is highly variable. The X-linked form usually gives rise to a severe phenotype in males presenting at birth with marked weakness and hypotonia, external ophthalmoplegia and respiratory failure. Signs of antenatal onset comprise reduced foetal movements, polyhydramnios and thinning of the ribs on chest radiographs; birth asphyxia may be the present. Affected infants are often macrosomic, with length above the 90th centile and large head circumference. Testes are frequently undescended. Both autosomal-recessive (AR) and autosomal-dominant (AD) forms differ from the X-linked form regarding age at onset, severity, clinical characteristics and prognosis. In general, AD forms have a later onset and milder course than the X-linked form, and the AR form is intermediate in both respects.Mutations in the myotubularin (MTM1) gene on chromosome Xq28 have been identified in the majority of patients with the X-linked recessive form, whilst AD and AR forms have been associated with mutations in the dynamin 2 (DNM2) gene on chromosome 19p13.2 and the amphiphysin 2 (BIN1) gene on chromosome 2q14, respectively. Single cases with features of CNM have been associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the hJUMPY (MTMR14) genes.Diagnosis is based on typical histopathological findings on muscle biopsy in combination with suggestive clinical features; muscle magnetic resonance imaging may complement clinical assessment and inform genetic testing in cases with equivocal features. Genetic counselling should be offered to all patients and families in whom a diagnosis of CNM has been made.The main differential diagnoses include congenital myotonic dystrophy and other conditions with severe neonatal hypotonia.Management of CNM is mainly supportive, based on a multidisciplinary approach. Whereas the X-linked form due to MTM1 mutations is often fatal in infancy, dominant forms due to DNM2 mutations and some cases of the recessive BIN1-related form appear to be associated with an overall more favourable prognosis.