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2.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 36(12): 1167-1170, 2019 Dec 10.
Artigo em Chinês | MEDLINE | ID: mdl-31813139

RESUMO

OBJECTIVE: To study the prevalence, clinical and genetic characteristics of primary carnitine deficiency (PCD). METHODS: From January 2013 to December 2017, 720 667 newborns and their mothers were tested for PCD by tandem mass spectrometry. Potential mutations of carnitine transporter gene SLC22A5 among suspected PCD patients were analyzed. Dietary guidance and L-carnitine supplementation were provided to the parents. Growth and intelligence development were surveyed during follow-up. RESULTS: In total 21 neonates and 6 mothers were diagnosed with PCD, which yielded an incidence of 1 in 34 317. Eighteen SLC22A5 mutations were detected, which included 4 novel mutations, namely c.1484T>C, c.394-1G>T, c.431T>C and c.265-266insGGCTCGCCACC. Eighteen patients were found to carry compound heterozygous mutations and 3 have carried homozygous SLC22A5 mutations. Three mothers carried compound heterozygous mutations and 2 carried homozygous mutations. Common mutations included c.1400C>G (42.3%), c.760C>T (11.5%) and c.51C>G (7.7%). During the 8-42 month follow-up, neonates with PCD showed no clinical symptoms but normal growth. Blood level of free carnitine was raised in all mothers after the treatment. CONCLUSION: The incidence of neonatal PCD in Henan is 1 in 34 317, with the most common mutation being c.1400C>G. Above finding has enriched the spectrum of SLC22A5 gene mutations.


Assuntos
Cardiomiopatias/genética , Carnitina/deficiência , Hiperamonemia/genética , Doenças Musculares/genética , Membro 5 da Família 22 de Carreadores de Soluto/genética , Cardiomiopatias/epidemiologia , Carnitina/administração & dosagem , Carnitina/genética , China , Feminino , Humanos , Hiperamonemia/epidemiologia , Recém-Nascido , Doenças Musculares/epidemiologia , Mutação , Triagem Neonatal
3.
Aust Vet J ; 97(12): 499-504, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31674019

RESUMO

BACKGROUND: Cervicothoracic vertebral subluxation in sheep presents as a postural and locomotor disorder, and has been described in several breeds in Australia and overseas. Cervical myopathy may also be present in these cases. CASE REPORT: A New South Wales sheep producer reported a postural and locomotor disorder with a low prevalence in his Poll Merino stud flock, affecting neonate, weaner and adult sheep. Animals with postural abnormalities, variable degrees of ataxia and proprioceptive deficits involving both fore and hind limbs were described. Abnormalities of the cervicothoracic vertebral column were identified grossly during necropsy, with misalignment and consequent narrowing of the posterior cervical spinal canal. Lesions ranging from pallor (cellular degeneration) to white streaky lesions with pinpoint haemorrhage (necrosis) were identified in the cervicothoracic paravertebral musculature of affected animals. Boney abnormalities were further characterised by imaging studies. Pedigree analysis of the very extensive breeding and disease incident records available for this flock suggested that the disease was inherited. A similar case recognised in a separate New South Wales Poll Merino flock is also described. CONCLUSION: This report describes an entity of cervicothoracic vertebral subluxation in two Poll Merino sheep flocks, with cervical myopathy also identified in one, with preliminary evidence in the primary case that there is likely to be a hereditary basis. The two cases outlined in this report resemble the findings of several historical investigations into ovine flock postural disorders in Australia and beyond.


Assuntos
Vértebras Cervicais/patologia , Doenças Musculares/veterinária , Doenças dos Ovinos/genética , Doenças dos Ovinos/patologia , Vértebras Torácicas/patologia , Animais , Autopsia/veterinária , Cruzamento , Eutanásia Animal , Doenças Musculares/genética , Doenças Musculares/patologia , New South Wales , Ovinos , Carneiro Doméstico
4.
Nat Commun ; 10(1): 4457, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575858

RESUMO

Mutations in genes encoding KATP channel subunits have been reported for pancreatic disorders and Cantú syndrome. Here, we report a syndrome in six patients from two families with a consistent phenotype of mild intellectual disability, similar facies, myopathy, and cerebral white matter hyperintensities, with cardiac systolic dysfunction present in the two oldest patients. Patients are homozygous for a splice-site mutation in ABCC9 (c.1320 + 1 G > A), which encodes the sulfonylurea receptor 2 (SUR2) subunit of KATP channels. This mutation results in an in-frame deletion of exon 8, which results in non-functional KATP channels in recombinant assays. SUR2 loss-of-function causes fatigability and cardiac dysfunction in mice, and reduced activity, cardiac dysfunction and ventricular enlargement in zebrafish. We term this channelopathy resulting from loss-of-function of SUR2-containing KATP channels ABCC9-related Intellectual disability Myopathy Syndrome (AIMS). The phenotype differs from Cantú syndrome, which is caused by gain-of-function ABCC9 mutations, reflecting the opposing consequences of KATP loss- versus gain-of-function.


Assuntos
Trifosfato de Adenosina/metabolismo , Canalopatias/metabolismo , Predisposição Genética para Doença/genética , Deficiência Intelectual/metabolismo , Doenças Musculares/metabolismo , Mutação , Receptores Sulfonilureia/genética , Receptores Sulfonilureia/metabolismo , Adolescente , Adulto , Sequência de Aminoácidos , Animais , Cardiomegalia/genética , Cardiomegalia/metabolismo , Linhagem Celular , Criança , Modelos Animais de Doenças , Facies , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/genética , Coração , Cardiopatias/genética , Cardiopatias/metabolismo , Homozigoto , Humanos , Hipertricose/genética , Hipertricose/metabolismo , Deficiência Intelectual/parasitologia , Masculino , Complexo Mediador/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Doenças Musculares/genética , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/metabolismo , Transtornos do Neurodesenvolvimento/fisiopatologia , Osteocondrodisplasias/genética , Osteocondrodisplasias/metabolismo , Linhagem , Fenótipo , Rubídio , Sequenciamento Completo do Genoma , Adulto Jovem , Peixe-Zebra
6.
Molecules ; 24(18)2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31500110

RESUMO

Carnitine plays essential roles in intermediary metabolism. In non-vegetarians, most of carnitine sources (~75%) are obtained from diet whereas endogenous synthesis accounts for around 25%. Renal carnitine reabsorption along with dietary intake and endogenous production maintain carnitine homeostasis. The precursors for carnitine biosynthesis are lysine and methionine. The biosynthetic pathway involves four enzymes: 6-N-trimethyllysine dioxygenase (TMLD), 3-hydroxy-6-N-trimethyllysine aldolase (HTMLA), 4-N-trimethylaminobutyraldehyde dehydrogenase (TMABADH), and γ-butyrobetaine dioxygenase (BBD). OCTN2 (organic cation/carnitine transporter novel type 2) transports carnitine into the cells. One of the major functions of carnitine is shuttling long-chain fatty acids across the mitochondrial membrane from the cytosol into the mitochondrial matrix for ß-oxidation. This transport is achieved by mitochondrial carnitine-acylcarnitine cycle, which consists of three enzymes: carnitine palmitoyltransferase I (CPT I), carnitine-acylcarnitine translocase (CACT), and carnitine palmitoyltransferase II (CPT II). Carnitine inborn errors of metabolism could result from defects in carnitine biosynthesis, carnitine transport, or mitochondrial carnitine-acylcarnitine cycle. The presentation of these disorders is variable but common findings include hypoketotic hypoglycemia, cardio(myopathy), and liver disease. In this review, the metabolism and homeostasis of carnitine are discussed. Then we present details of different inborn errors of carnitine metabolism, including clinical presentation, diagnosis, and treatment options. At the end, we discuss some of the causes of secondary carnitine deficiency.


Assuntos
Cardiomiopatias/genética , Carnitina/deficiência , Carnitina/genética , Hiperamonemia/genética , Erros Inatos do Metabolismo/genética , Mitocôndrias/enzimologia , Doenças Musculares/genética , Aldeído Oxirredutases/genética , Cardiomiopatias/metabolismo , Carnitina/biossíntese , Carnitina/metabolismo , Carnitina Aciltransferases/genética , Carnitina O-Palmitoiltransferase/genética , Humanos , Hiperamonemia/metabolismo , Mitocôndrias/genética , Oxigenases de Função Mista/genética , Doenças Musculares/metabolismo , Oxirredução , Membro 5 da Família 22 de Carreadores de Soluto/genética , gama-Butirobetaína Dioxigenase/genética
8.
Handb Clin Neurol ; 162: 435-448, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31324324

RESUMO

The differential diagnosis of neonatal hypotonia is a complex task, as in newborns hypotonia can be the presenting sign of different underlying causes, including peripheral and central nervous system involvement and genetic and metabolic diseases. This chapter describes how a combined approach, based on the combination of clinical signs and new genetic techniques, can help not only to establish when the hypotonia is related to peripheral involvement but also to achieve an accurate and early diagnosis of the specific neuromuscular diseases with neonatal onset. The early identification of such disorders is important, as this allows early intervention with disease-specific standards of care and, more importantly, because of the possibility to treat some of them, such as spinal muscular atrophy, with therapeutic approaches that have recently become available.


Assuntos
Doenças do Recém-Nascido/terapia , Hipotonia Muscular/congênito , Hipotonia Muscular/terapia , Doenças Musculares/congênito , Doenças Musculares/terapia , Adulto , Feminino , Humanos , Recém-Nascido , Doenças do Recém-Nascido/diagnóstico , Doenças do Recém-Nascido/genética , Doenças do Recém-Nascido/fisiopatologia , Técnicas de Diagnóstico Molecular , Hipotonia Muscular/diagnóstico , Hipotonia Muscular/genética , Doenças Musculares/diagnóstico , Doenças Musculares/genética , Gravidez
9.
Acta Myol ; 38(2): 33-36, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31309180

RESUMO

Mutations in the LMNA gene are associated with a wide spectrum of disease phenotypes, ranging from neuromuscular, cardiac and metabolic disorders to premature aging syndromes. Skeletal muscle involvement may present with different phenotypes: limb-girdle muscular dystrophy type 1B or LMNA-related dystrophy; autosomal dominant Emery-Dreifuss muscular dystrophy; and a congenital form of muscular dystrophy, frequently associated with early onset of arrhythmias. Heart involvement may occur as part of the muscle involvement or independently, regardless of the presence of the myopathy. Notably conduction defects and dilated cardiomyopathy may exist without a muscle disease. This paper will focus on cardiac diseases presenting as the first manifestation of skeletal muscle hereditary disorders such as laminopathies, inspired by two large families with cardiovascular problems long followed by conventional cardiologists who did not suspect a genetic muscle disorder underlying these events. Furthermore it underlines the need for a multidisciplinary approach in these disorders and how the figure of the cardio-myo-geneticist may play a key role in facilitating the diagnostic process, and addressing the adoption of appropriate prevention measures.


Assuntos
Cardiopatias/etiologia , Lamina Tipo A/genética , Doenças Musculares/diagnóstico , Doenças Musculares/genética , Mutação/genética , Adolescente , Adulto , Feminino , Cardiopatias/diagnóstico , Cardiopatias/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Adulto Jovem
10.
Biomarkers ; 24(7): 659-665, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31342800

RESUMO

Introduction: Statin, the first-line treatment for dyslipidaemia, may have suboptimal adherence due to its associated muscle adverse events. These data, however, remain limited. Aim: To determine the association of serum creatine kinase (CK) and SLCO1B1 rs4363657 polymorphism with statin-associated muscle adverse events (SAMAE) among dyslipidaemia participants. Methods: This was a prospective cohort study at government health clinics involving newly diagnosed adults with dyslipidaemia. SAMAE were recorded based on the patient's complaint after a month on statin. CK was taken at baseline and follow-up. Genetic profiling was performed for SLCO1B1 rs4363657 polymorphism. Results: Among 118 participants, majority were Malay (72%) males (61%) with a mean age of 49 ± 12.2 years old and prescribed lovastatin (61.9). There was a significant association between statin types (lovastatin and simvastatin) and SAMAE (p = 0.0327); no significant association noted between CK and SAMAE (p = 0.5637). The SLCO1B1 rs4363657 polymorphism was significantly associated SAMAE (p < 0.0001). Conclusions: In this first pilot study of a multiethnic Malaysian population, the incidence of SAMAE was 18.6%. SAMAE were significantly higher in subjects on lovastatin compared to simvastatin. SLCO1B1 rs4363657 polymorphism was a significant risk factor for SAMAE.


Assuntos
Dislipidemias/complicações , Transportador 1 de Ânion Orgânico Específico do Fígado/genética , Lovastatina/efeitos adversos , Doenças Musculares/etiologia , Polimorfismo Genético , Adulto , Feminino , Humanos , Incidência , Malásia , Masculino , Pessoa de Meia-Idade , Doenças Musculares/induzido quimicamente , Doenças Musculares/genética , Projetos Piloto , Estudos Prospectivos , Fatores de Risco , Sinvastatina/efeitos adversos
11.
J Neuromuscul Dis ; 6(3): 289-305, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31356215

RESUMO

Muscle contraction requires specialized membrane structures with precise geometry and relies on the concerted interplay of electrical stimulation and Ca2+ release, known as excitation-contraction coupling (ECC). The membrane structure hosting ECC is called triad in skeletal muscle and dyad in cardiac muscle, and structural or functional defects of triads and dyads have been observed in a variety of myopathies and cardiomyopathies. Based on their function, the proteins localized at the triad/dyad can be classified into three molecular pathways: the Ca2+ release complex (CRC), store-operated Ca2+ entry (SOCE), and membrane remodeling. All three are mechanistically linked, and consequently, aberrations in any of these pathways cause similar disease entities. This review provides an overview of the clinical and genetic spectrum of triad and dyad defects with a main focus of attention on the underlying pathomechanisms.


Assuntos
Cálcio/metabolismo , Cardiomiopatias/metabolismo , Acoplamento Excitação-Contração/fisiologia , Doenças Musculares/metabolismo , Animais , Cardiomiopatias/genética , Homeostase , Humanos , Músculo Esquelético/metabolismo , Doenças Musculares/genética , Miocárdio/metabolismo
12.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 36(7): 690-693, 2019 Jul 10.
Artigo em Chinês | MEDLINE | ID: mdl-31302912

RESUMO

OBJECTIVE: To carry out mutation analysis and prenatal diagnosis for a family affected with primary carnitine deficiency. METHODS: Genomic DNA of the proband was extracted from peripheral blood sample 10 days after birth. The 10 exons and intron/exon boundaries of the SLC22A5 gene were subjected to PCR amplification and Sanger sequencing. The proband's mother was pregnant again two years after his birth. Fetal DNA was extracted from amniocytes and subjected to PCR and Sanger sequencing. RESULTS: Tandem mass spectrometric analysis of the proband revealed low level of plasma-free carnitine whilst organic acids in urine was normal. Compound heterozygous SLC22A5 mutations c.1195C>T (inherited from his father) and c.517delC (inherited from his mother) were detected in the proband. Prenatal diagnosis has detected no mutation in the fetus. The plasma-free carnitine was normal after birth. CONCLUSION: Appropriate genetic testing and prenatal diagnosis can prevent further child with carnitine deficiency. The identification of c.517delC, a novel mutation, enriched the spectrum of SLC22A5 mutations.


Assuntos
Cardiomiopatias/genética , Carnitina/deficiência , Hiperamonemia/genética , Doenças Musculares/genética , Membro 5 da Família 22 de Carreadores de Soluto/genética , Carnitina/genética , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Mutação , Gravidez , Diagnóstico Pré-Natal
13.
Mol Biol Cell ; 30(15): 1786-1790, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31306095

RESUMO

Laminopathies are a diverse group of rare diseases with various pathologies in different tissues, which are linked to mutations in the LMNA gene. Historically, the structural disease model proposed mechanical defects of the lamina and nuclear fragility, the gene expression model impairment of spatial chromatin organization and signaling pathways as underlying mechanisms leading to the pathologies. Exciting findings in the past few years showing that mechanical forces are directly transmitted into the nucleus, where they affect chromatin organization and mechanoresponsive signaling molecules, have led to a revised concept of an integrative unified disease model, in which lamin-mediated pathways in mechanotransduction and chromatin regulation are highly interconnected and mutually dependent. In this Perspective we highlight breakthrough findings providing new insight into lamin-linked mechanisms of mechanotransduction and chromatin regulation and discuss how a combined and interrelated impairment of these functions by LMNA mutations may impair the complex mechanosignaling network and cause tissue-specific pathologies in laminopathies.


Assuntos
Regulação da Expressão Gênica , Lamina Tipo A/química , Lamina Tipo A/genética , Modelos Biológicos , Doenças Musculares/genética , Animais , Humanos , Mecanotransdução Celular
14.
Poult Sci ; 98(11): 5465-5476, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31250001

RESUMO

During recent years, research on meat quality in poultry has aimed to evaluate the presence and consequences of breast myopathies as well as the factors which can affect their occurrence by modifying the growth rate. A total of 900 broiler chickens were reared until slaughter (48 D) to evaluate the effect of 2 genetic lines (A vs. B) and feeding plans (ad libitum [AL], early restricted [ER], from 13 to 23 D of age, and late restricted [LR], from 27 to 37 D of age; restriction rate: 80%) on performance, meat quality, and breast muscle myopathies. Calsequestrin and vascular endothelial growth factor (VEGF) expressions, and muscle fiber degeneration (MFD) were recorded at 22, 36, and 48 D. Chickens in the AL treatment had greater final live (P < 0.01) and carcass weights and proportion of pectoralis major muscle (P = 0.04) compared to chickens in the LR treatment, whereas chickens in the ER treatment had intermediate final live (3,454 g) and carcass weights, and proportion of pectoralis major muscle (25.6%). Chickens of line A were heavier than chickens of line B (P < 0.001), and had a greater feed conversion rate. Chickens of line A also had a greater dressing out percentage (P < 0.001), but a lower proportion of pectoralis major muscle (P = 0.04), as well as a greater meat pH (P < 0.001), meat cooking losses (P < 0.01), and shear force of the pectoralis major muscle (P = 0.03). Calsequestrin and VEGF mRNA were significantly lower in ER and LR chickens compared to AL chickens after feed restriction and during refeeding (P < 0.05). MFD scores increased with chicken age (P < 0.001) and differed between genetic lines (P < 0.001). Neither feeding plan nor genetic line affected the occurrence of white striping or wooden breast condition.


Assuntos
Proteínas Aviárias/genética , Galinhas/fisiologia , Dieta/veterinária , Expressão Gênica , Doenças Musculares/veterinária , Doenças das Aves Domésticas/epidemiologia , Fatores Etários , Ração Animal/análise , Animais , Proteínas Aviárias/metabolismo , Calsequestrina/genética , Calsequestrina/metabolismo , Galinhas/genética , Galinhas/crescimento & desenvolvimento , Masculino , Doenças Musculares/epidemiologia , Doenças Musculares/etiologia , Doenças Musculares/genética , Músculos Peitorais/patologia , Doenças das Aves Domésticas/etiologia , Doenças das Aves Domésticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Distribuição Aleatória , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Redox Biol ; 26: 101232, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31181458

RESUMO

There is more skeletal muscle tissue in the body than any other tissue and, as it is the organ of the majority of metabolic activity, muscle defect can affect the health of the entire body. Endoplasmic reticulum (ER) stress due to defects in protein folding/degradation balance, altered calcium and lipid levels and alterations in ER-mitochondria contacts has recently been recognised as the pathogenic cause of many different myopathies. In addition, a maladaptive ER stress response triggered by ER stress and mediated by three ER stress sensors (PERK, IRE1 and ATF6) is involved in a failure to relieve muscle tissue from this stress. Targeting ER stress and the ER stress response pathway offers a broad range of opportunities for treating myopathies but, as the inhibition of the three ER stress sensors may not be safe because it could lead to unexpected effects; it therefore calls for careful analysis of the changes in downstream signal transduction in the different myopathies so these sub-pathways can be pharmacologically targeted. This review summarises the known inhibitors of the ER stress response and the successful results obtained using some of them in mouse models of muscle diseases caused by ER stress/ER stress response.


Assuntos
Retículo Endoplasmático/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Doenças Musculares/tratamento farmacológico , Fenilbutiratos/farmacologia , Sulfonamidas/farmacologia , Tiofenos/farmacologia , Fator 6 Ativador da Transcrição/antagonistas & inibidores , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Adenina/análogos & derivados , Adenina/farmacologia , Aldeídos/farmacologia , Animais , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/patologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Endorribonucleases/antagonistas & inibidores , Endorribonucleases/genética , Endorribonucleases/metabolismo , Humanos , Indóis/farmacologia , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Terapia de Alvo Molecular/métodos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/patologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Doenças Musculares/genética , Doenças Musculares/metabolismo , Doenças Musculares/patologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , eIF-2 Quinase/antagonistas & inibidores , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo
16.
BMC Med Genet ; 20(1): 78, 2019 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-31068177

RESUMO

BACKGROUND: Few manuscripts have reported phenotypes of skeletal muscle myopathies caused by mutations in the head region of slow/cardiac beta-myosin heavy chain (MyHCI). Among the patients, some of them showed the phenotype of skeletal muscle weakness with the obvious clinical features of cardiomyopathy while others showed pure skeletal muscle weakness with no symptoms of cardiac involvement. Genotype-phenotype relationship regarding the effect of a mutation on MyHCI is complex. Questions regarding why some mutations cause cardiomyopathy or skeletal muscle disorders alone or a combination of both still need to be answered. More findings in genetic variation are needed to extend knowledge of mutations in the MYH7 gene linked to skeletal muscle disorders. CASE PRESENTATION: Here we present a female adult patient with a phenotype of childhood onset of muscular disorders and predominant involvement of thigh muscles with biopsy showing intrasarcoplasmic inclusion bodies. Whole exome sequencing showed that variant c.1370 T > G (p.Ile457Arg) in the MYH7 gene is a missense mutation possibly linked to the clinical findings. Our patient likely shows an uncharacteristic myosin storage myopathy associated with respiratory and cardiac involvement linked to a missense mutation in the head of MyHCI. CONCLUSIONS: Given this mutation is located within the motor domain of MyHCI, this might affect the regulation of myosin mechano-chemical activity during the contractile cycle. Consequently, this potentially damaging effect can be easily amplified within the network of ~ 300-myosin molecules forming the thick filament and therefore become cumulatively deleterious, affecting, in turn, the overall organization and performance of sarcomere.


Assuntos
Miosinas Cardíacas/genética , Doenças Musculares/congênito , Mutação de Sentido Incorreto , Cadeias Pesadas de Miosina/genética , Adulto , Criança , Feminino , Humanos , Pessoa de Meia-Idade , Doenças Musculares/genética , Fenótipo
18.
J Clin Neuromuscul Dis ; 20(4): 214-216, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31135626

RESUMO

We describe a 57-year-old patient with mild diffuse weakness that was incidentally detected when he was evaluated for restless leg syndrome. An electromyography confirmed the presence of a myopathy without suggestion of inflammatory myopathy. A muscle biopsy demonstrated type 1 fiber predominance with minimal inflammatory features suggesting a genetic myopathy. Exome sequencing revealed c.10648C > T variant (p.R3550W), and a novel variant, c.10749_10753delGGAGG (E3584Rfs*3), in the ryanodine receptor 1 (RYR1) gene transmitted through his asymptomatic father indicating these mutations are in trans. Prompted by these results, a 47-year-old sister presented for evaluation. Her examination showed mild proximal muscle weakness, and an electromyography confirmed a noninflammatory myopathy. Her genotype was identical to her affected brother confirming that in these siblings, the RYR1 mutations, transmitted in an autosomal recessive pattern, are the cause of their myopathy. The adult age at diagnosis of these affected siblings likely reflects the mild and minimally progressive nature of the myopathy.


Assuntos
Doenças Musculares/diagnóstico , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Eletromiografia , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Musculares/genética , Mutação
19.
Orphanet J Rare Dis ; 14(1): 100, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060578

RESUMO

BACKGROUND: TK2 gene encodes for mitochondrial thymidine kinase, which phosphorylates the pyrimidine nucleosides thymidine and deoxycytidine. Recessive mutations in the TK2 gene are responsible for the 'myopathic form' of the mitochondrial depletion/multiple deletions syndrome, with a wide spectrum of severity. METHODS: We describe 18 patients with mitochondrial myopathy due to mutations in the TK2 gene with absence of clinical symptoms until the age of 12. RESULTS: The mean age of onset was 31 years. The first symptom was muscle limb weakness in 10/18, eyelid ptosis in 6/18, and respiratory insufficiency in 2/18. All patients developed variable muscle weakness during the evolution of the disease. Half of patients presented difficulty in swallowing. All patients showed evidence of respiratory muscle weakness, with need for non-invasive Mechanical Ventilation in 12/18. Four patients had deceased, all of them due to respiratory insufficiency. We identified common radiological features in muscle magnetic resonance, where the most severely affected muscles were the gluteus maximus, semitendinosus and sartorius. On muscle biopsies typical signs of mitochondrial dysfunction were associated with dystrophic changes. All mutations identified were previously reported, being the most frequent the in-frame deletion p.Lys202del. All cases showed multiple mtDNA deletions but mtDNA depletion was present only in two patients. CONCLUSIONS: The late-onset is the less frequent form of presentation of the TK2 deficiency and its natural history is not well known. Patients with late onset TK2 deficiency have a consistent and recognizable clinical phenotype and a poor prognosis, due to the high risk of early and progressive respiratory insufficiency.


Assuntos
Miopatias Mitocondriais/enzimologia , Timidina Quinase/deficiência , Adolescente , Adulto , Criança , DNA Mitocondrial/genética , Feminino , Humanos , Transtornos de Início Tardio/enzimologia , Transtornos de Início Tardio/metabolismo , Transtornos de Início Tardio/patologia , Masculino , Pessoa de Meia-Idade , Miopatias Mitocondriais/genética , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Doenças Musculares/enzimologia , Doenças Musculares/genética , Mutação/genética , Estudos Retrospectivos , Timidina Quinase/genética , Adulto Jovem
20.
Mol Genet Metab ; 127(1): 64-73, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31031081

RESUMO

BACKGROUND: Very-Long-Chain Acyl-CoA Dehydrogenase (VLCAD) deficiency is a disorder of fatty acid oxidation included in the recommended uniform newborn screening (NBS) panel in the USA. It can have variable clinical severity and there is limited information on the natural history of this condition, clinical presentation according to genotype and effectiveness of newborn screening. METHODS: Retrospective data (growth parameters, morbidity, biochemical and genetic testing results) were collected from patients with VLCAD deficiency, to evaluate biochemical and clinical outcomes. Descriptive statistics was used for qualitative variables, while linear regression analysis was used to correlate continuous variables. RESULTS: VLCAD deficiency (screened by measuring elevated levels of C14:1-carnitine in blood spots) was more frequent in Utah than the national average (1:27,617 versus 1:63,481) in the first ten years of screening. Twenty-six patients had a confirmed diagnosis of VLCAD deficiency using DNA testing or functional studies. The c.848T>C (p.V283A) variant in the ACADVL gene was the most frequent in our population. Novel variants (c.623-21A>G (IVS7-21A>G); c.1052C>T (p.T351I); c.1183-7A>G (IVS11-7A>G); c.1281G>C (p.W427C); c.1923G>C (p.L641F); c.1924G>A (p.V642M)) were identified in this study, with their pathogenicity remaining unclear in most cases. C14:1-carnitine levels decreased with age and significantly correlated with CK levels as index of muscle involvement. There were no cases of HELLP syndrome nor liver disease during pregnancies in the mothers of VLCAD patients. None of our patients developed cardiac involvement after birth and all patients had normal growth parameters while on treatment. Clinical manifestations were related to concomitant infections and altered biochemical parameters. DISCUSSION: VLCAD deficiency can be identified by neonatal screening. Most patients compliant with therapy normalized biochemical parameters and had no major clinical manifestations. Complications were completely prevented with a relatively low number of pre-emptive ER visits or hospital admissions. It remains unclear whether neonatal screening is now identifying less severely affected patient or if complications will arise as subjects become older. Observation beyond puberty is necessary to fully understand the impact of VLCAD deficiency on morbidity in patients with VLCAD deficiency.


Assuntos
Acil-CoA Desidrogenase de Cadeia Longa/deficiência , Variação Genética , Erros Inatos do Metabolismo Lipídico/diagnóstico , Erros Inatos do Metabolismo Lipídico/genética , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/genética , Doenças Musculares/diagnóstico , Doenças Musculares/genética , Triagem Neonatal , Acil-CoA Desidrogenase de Cadeia Longa/genética , Adolescente , Carnitina/sangue , Criança , Pré-Escolar , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Erros Inatos do Metabolismo Lipídico/terapia , Masculino , Doenças Mitocondriais/terapia , Morbidade , Doenças Musculares/terapia , Estudos Retrospectivos , Resultado do Tratamento , Utah , Adulto Jovem
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