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BACKGROUND Neurodevelopmental disorders (NDD) are umbrella disorders that encompass global developmental delay (GDD), intellectual disability, autism spectrum disorders, motor developmental disorders, and sleep disorders. Both GDD and autism spectrum disorder are common and yet clinically and genetically heterogeneous disorders. Despite their high prevalence and the advent of sequencing detection methods, the genomic etiology of GDD and autism spectrum disorder in most patients is largely unknown. CASE REPORT In this study, we describe a 6-year-old girl with GDD, autistic features, and structural brain abnormalities, including a moderate reduction in periventricular white matter and bilateral optic nerve hypoplasia, Chiari malformation type I with normal myelinization. A comprehensive joint whole-genome analysis (WGS) of the proband and her unaffected parents was performed. The trio-WGS analysis identified novel de novo nonsense variants AGO3: c.1324C>T (p.Gln442*) and KHSRP: c.1573C>T (p.Gln525*). These variants have not been reported in gnomAD and published literature. AGO3 and KHSRP are not currently associated with a known phenotype in the Online Mendelian Inheritance in Man (OMIM); however, they may be involved in neuronal development. CONCLUSIONS This report highlights the utility of joint WGS analysis in identifying novel de novo genomic alterations in a patient with the spectrum of phenotypes of GDD and neurodevelopmental disorders. The role of these variants and genes in GDD requires further studies.
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Trastorno del Espectro Autista , Discapacidades del Desarrollo , Humanos , Femenino , Niño , Trastorno del Espectro Autista/genética , Discapacidades del Desarrollo/genética , Codón sin Sentido , Secuenciación Completa del GenomaRESUMEN
ATM gene is implicated in the development of breast cancer in the heterozygous state, and Ataxia-telangiectasia (A-T) in a homozygous or compound heterozygous state. Ataxia-telangiectasia (A-T) is a rare cerebellar ataxia syndrome presenting with progressive neurologic impairment, telangiectasia, and an increased risk of leukemia and lymphoma. Although the role of ATM, separately, in association with A-T and breast cancer is well documented, there is a limited number of studies investigating ATM variants when segregating with both phenotypes in the same family. Here, using joint analysis and whole genome sequencing, we investigated ATM c.1564_1565del in a family with one homozygous member presenting with A-T (OMIM # 208900) and three heterozygous members, of whom one had breast cancer (OMIM #114480). To our knowledge, this is the first study of ATM c.1564_1565del segregation with both A-T and breast cancer phenotypes within the same kindred. This study highlights the need for a comprehensive genomic approach in the appropriate cancer risk management of heterozygote carriers of ATM in families with A-T.
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Proteínas de la Ataxia Telangiectasia Mutada , Ataxia Telangiectasia , Neoplasias de la Mama , Linaje , Humanos , Ataxia Telangiectasia/genética , Femenino , Neoplasias de la Mama/genética , Proteínas de la Ataxia Telangiectasia Mutada/genética , Adulto , Masculino , Predisposición Genética a la Enfermedad , Persona de Mediana Edad , Secuenciación Completa del Genoma , HeterocigotoRESUMEN
PURPOSE: An investigation for the co-occurrence of two unrelated genetic disorders of muscular dystrophy and Prader-Willi syndrome (PWS) (OMIM#176270) using joint whole genome sequencing (WGS). METHODS: Trio WGS joint analysis was performed to investigate the genetic etiology in a proband with PWS, prolonged muscular hypotonia associated hyperCKemia, and early-onset obesity. The parents were unaffected. RESULTS: Results showed maternal isodisomy uniparental disomy (UPD) in chromosome 15, expanding from 15q11.2 to 15q22.2, including PWS regions at 15q11.2-15q13. Maternal heterodisomy was detected from 15q22.2 to 15q26.3. A pathogenic variant, NM_000070.3(CAPN3):c.550del (p.Thr184fs), was identified at 15q15.1 in a heterozygous state in the mother that was homozygous in the proband due to maternal isodisomy. CONCLUSION: This is the first study of the concurrent molecular etiology of PWS and calpainopathy (OMIM#253600) in the same patient. This report highlights the utility of joint analysis and the need for the assessment of autosomal recessive disease in regions of isodisomy in patients with complex and unexplained phenotypes.
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Calpaína , Cromosomas Humanos Par 15 , Síndrome de Prader-Willi , Disomía Uniparental , Humanos , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , Síndrome de Prader-Willi/patología , Calpaína/genética , Femenino , Cromosomas Humanos Par 15/genética , Disomía Uniparental/genética , Secuenciación Completa del Genoma , Masculino , Proteínas MuscularesRESUMEN
INTRODUCTION: Existing data on fragility spinal fractures prevalence in liver transplant candidates are scarce and inconsistent. This may be due to other comorbidities, besides hepatic osteodystrophy (HO), that contribute to bone loss and fragility fracture prevalence in chronic liver disease (CLD). OBJECTIVES: The aim of this study was to investigate the prevalence of spinal thoracic and lumbar fragility fractures among cirrhotic, non-chronic kidney disease (CKD), non-diabetic liver transplant candidates and to explore their relationship with clinical characteristics, laboratory markers and dual-energy x-ray absorptiometry (DXA) results. MATERIAL AND METHODS: This cross-sectional observational study was conducted at Merkur University Hospital, Croatia, between February 2019 and May 2023. Adult patients with liver cirrhosis referred for liver transplantation were included. Patients with acute infection, CKD, diabetes mellitus, malignancies, inflammatory bone diseases and those on corticosteroid or antiresorptive therapy were excluded. Clinical, laboratory and radiological assessment was carried out and patients were accordingly allocated into non-fractured and fractured group for the purpose of statistical analysis. RESULTS: A total of 90 patients were included in the study. There was 123 fractures, 87 (70.7 %) in the thoracic and 36 (29.3 %) in the lumbar region. Eighty-nine (72.4 %) fractures were grade 1, 31 (25.2 %) were grade 2 and 3 (2.4 %) were grade 3. Patients in the fractured group were significantly older (p < 0.001). No significant differences between fractured and non-fractured group according to laboratory and DXA parameters were noted. Subgroup with lumbar fractures had significantly lower bone mineral density values at L1-L4 region. Statistically significant negative correlation between bone specific alkaline phosphatase (BALP) and hip total BMD (rho = -0.414, p < 0.001) and spine total BMD (rho = -0.258, p = 0.014) values was found. CONCLUSION: Present study confirmed detrimental impact of CLD and HO on bone strength. DXA measurement correlated with the presence of lumbar fragility fractures. A combination of standard X-ray imaging and DXA is needed for adequate bone evaluation in pretransplant period and BALP could be useful for detecting HO in CLD. Searching for other risk factors and implementing bone turnover markers and additional imaging techniques for bone loss evaluation in liver transplant candidates is needed.
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Cirrosis Hepática , Trasplante de Hígado , Fracturas de la Columna Vertebral , Adulto , Humanos , Absorciometría de Fotón/métodos , Densidad Ósea , Enfermedades Óseas Metabólicas , Croacia/epidemiología , Estudios Transversales , Cirrosis Hepática/epidemiología , Vértebras Lumbares/diagnóstico por imagen , Insuficiencia Renal Crónica/epidemiología , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/epidemiologíaRESUMEN
Gabriele-de Vries syndrome is a rare autosomal dominant genetic disease caused by de novo pathogenic variants in the Yin Yang 1 (YY1) gene. Individuals with this syndrome present with multiple congenital anomalies, as well as a delay in development and intellectual disability. Herein, we report the case of a newborn male patient with a novel de novo pathogenic variant in the Guanine Nucleotide-Binding Protein, Alpha Stimulating (GNAS) gene, which was identified by whole-exome sequencing. Our patient suffered from a large open spinal dysraphism which was treated surgically immediately after birth. During the follow-up, facial dysmorphism, bladder and bowel incontinence, and mildly delayed motor and speech development were observed. Congenital central nervous system disorders were also confirmed radiologically. In this case report, we present our diagnostic and treatment approaches to this patient. To our knowledge, this is the first reported case of Gabriele-de Vries syndrome presenting with spinal dysraphism. Extensive genetic evaluation is the cornerstone in treatment of patients with suspected Gabriele-de Vries syndrome. However, in cases with potentially life-threatening conditions, surgery should be strongly considered.
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BACKGROUND: Hyperammonemic encephalopathy in newborns with urea cycle disorders and certain organic acidurias can cause severe brain injury, coma and death. Standard therapy includes protein restriction, nitrogen-scavenging drugs, prevention of catabolism and hemodialysis. Neuroprotective hypothermia as part of the treatment has been reported only 3 times. It has been suggested that mild systemic hypothermia can contribute to better neurological outcomes in hyperammonemic encephalopathy. However, the limited experience precludes accurate conclusions on safety and efficacy. METHODS: Whole body therapeutic hypothermia was included in the standard treatment of hyperammonemic encephalopathy in 4 neonates with urea cycle disorder or organic aciduria. RESULTS: Two patients survived the initial crisis. One patient has a developmental quotient of 0.8, while the other shows severe developmental delay. The cooling protocol had to be discontinued in 3 patients due to the otherwise untreatable complications (hypotension and hemorrhage). CONCLUSION: The efficacy and safety of therapeutic hypothermia in the treatment of neonatal hyperammonemic encephalopathy depend on various factors, requiring further evaluation.
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Hiperamonemia/terapia , Hipotermia Inducida/métodos , Hipoxia-Isquemia Encefálica/terapia , Trastornos Innatos del Ciclo de la Urea/terapia , Urea/metabolismo , Humanos , Hiperamonemia/patología , Hipoxia-Isquemia Encefálica/complicaciones , Recién Nacido , Resultado del Tratamiento , Trastornos Innatos del Ciclo de la Urea/complicaciones , Trastornos Innatos del Ciclo de la Urea/genética , Trastornos Innatos del Ciclo de la Urea/patologíaRESUMEN
BACKGROUND: Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ channels is an essential signaling pathway in many cell types. Ca2+ release-activated Ca2+ channels are formed by ORAI1, ORAI2, and ORAI3 proteins and activated by stromal interaction molecule (STIM) 1 and STIM2. Mutations in the ORAI1 and STIM1 genes that abolish SOCE cause a combined immunodeficiency (CID) syndrome that is accompanied by autoimmunity and nonimmunologic symptoms. OBJECTIVE: We performed molecular and immunologic analysis of patients with CID, anhidrosis, and ectodermal dysplasia of unknown etiology. METHODS: We performed DNA sequencing of the ORAI1 gene, modeling of mutations on ORAI1 crystal structure, analysis of ORAI1 mRNA and protein expression, SOCE measurements, immunologic analysis of peripheral blood lymphocyte populations by using flow cytometry, and histologic and ultrastructural analysis of patient tissues. RESULTS: We identified 3 novel autosomal recessive mutations in ORAI1 in unrelated kindreds with CID, autoimmunity, ectodermal dysplasia with anhidrosis, and muscular dysplasia. The patients were homozygous for p.V181SfsX8, p.L194P, and p.G98R mutations in the ORAI1 gene that suppressed ORAI1 protein expression and SOCE in the patients' lymphocytes and fibroblasts. In addition to impaired T-cell cytokine production, ORAI1 mutations were associated with strongly reduced numbers of invariant natural killer T and regulatory T (Treg) cells and altered composition of γδ T-cell and natural killer cell subsets. CONCLUSION: ORAI1 null mutations are associated with reduced numbers of invariant natural killer T and Treg cells that likely contribute to the patients' immunodeficiency and autoimmunity. ORAI1-deficient patients have dental enamel defects and anhidrosis, representing a new form of anhidrotic ectodermal dysplasia with immunodeficiency that is distinct from previously reported patients with anhidrotic ectodermal dysplasia with immunodeficiency caused by mutations in the nuclear factor κB signaling pathway (IKBKG and NFKBIA).
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Displasia Ectodérmica/genética , Síndromes de Inmunodeficiencia/genética , Proteína ORAI1/genética , Calcio/metabolismo , Células Cultivadas , Preescolar , Resultado Fatal , Femenino , Humanos , Lactante , Masculino , Modelos Moleculares , MutaciónRESUMEN
Ca2+ signals were reported to control lipid homeostasis, but the Ca2+ channels and pathways involved are largely unknown. Store-operated Ca2+ entry (SOCE) is a ubiquitous Ca2+ influx pathway regulated by stromal interaction molecule 1 (STIM1), STIM2, and the Ca2+ channel ORAI1. We show that SOCE-deficient mice accumulate pathological amounts of lipid droplets in the liver, heart, and skeletal muscle. Cells from patients with loss-of-function mutations in STIM1 or ORAI1 show a similar phenotype, suggesting a cell-intrinsic role for SOCE in the regulation of lipid metabolism. SOCE is crucial to induce mobilization of fatty acids from lipid droplets, lipolysis, and mitochondrial fatty acid oxidation. SOCE regulates cyclic AMP production and the expression of neutral lipases as well as the transcriptional regulators of lipid metabolism, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), and peroxisome proliferator-activated receptor α (PPARα). SOCE-deficient cells upregulate lipophagy, which protects them from lipotoxicity. Our data provide evidence for an important role of SOCE in lipid metabolism.
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Calcio/metabolismo , Lipólisis/genética , Transcripción Genética , Adenilil Ciclasas/metabolismo , Animales , Ácidos Grasos/metabolismo , Células HEK293 , Humanos , Lipasa/metabolismo , Gotas Lipídicas/metabolismo , Ratones , Mitocondrias/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/ultraestructura , Oxidación-Reducción , PPAR alfa/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Transducción de Señal/genética , Regulación hacia Arriba/genéticaRESUMEN
Eccrine sweat glands are essential for sweating and thermoregulation in humans. Loss-of-function mutations in the Ca2+ release-activated Ca2+ (CRAC) channel genes ORAI1 and STIM1 abolish store-operated Ca2+ entry (SOCE), and patients with these CRAC channel mutations suffer from anhidrosis and hyperthermia at high ambient temperatures. Here we have shown that CRAC channel-deficient patients and mice with ectodermal tissue-specific deletion of Orai1 (Orai1K14Cre) or Stim1 and Stim2 (Stim1/2K14Cre) failed to sweat despite normal sweat gland development. SOCE was absent in agonist-stimulated sweat glands from Orai1K14Cre and Stim1/2K14Cre mice and human sweat gland cells lacking ORAI1 or STIM1 expression. In Orai1K14Cre mice, abolishment of SOCE was associated with impaired chloride secretion by primary murine sweat glands. In human sweat gland cells, SOCE mediated by ORAI1 was necessary for agonist-induced chloride secretion and activation of the Ca2+-activated chloride channel (CaCC) anoctamin 1 (ANO1, also known as TMEM16A). By contrast, expression of TMEM16A, the water channel aquaporin 5 (AQP5), and other regulators of sweat gland function was normal in the absence of SOCE. Our findings demonstrate that Ca2+ influx via store-operated CRAC channels is essential for CaCC activation, chloride secretion, and sweat production in humans and mice.
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Señalización del Calcio/fisiología , Canales de Cloruro/metabolismo , Proteínas de Neoplasias/metabolismo , Proteína ORAI1/metabolismo , Glándulas Sudoríparas/metabolismo , Sudor/metabolismo , Animales , Anoctamina-1 , Acuaporina 5/genética , Acuaporina 5/metabolismo , Canales de Cloruro/genética , Femenino , Humanos , Masculino , Ratones , Ratones Noqueados , Proteínas de Neoplasias/genética , Proteína ORAI1/genética , Molécula de Interacción Estromal 1/genética , Molécula de Interacción Estromal 1/metabolismo , Molécula de Interacción Estromal 2/genética , Molécula de Interacción Estromal 2/metabolismoRESUMEN
Hyperinsulinism-hyperammonemia (HI/HA) syndrome is a rare autosomal dominant disease characterized by recurrent hypoglycemia and persistent mild elevation of plasma ammonia. HI/HA syndrome is one of the more common forms of congenital hyperinsulinism (CHI), caused by activating mutations within the GLUD1 gene that encodes the mitochondrial enzyme glutamate dehydrogenase (GDH). We report here on monozygotic twin girls presented with fasting- and protein-induced hypoglycemia and mild persistent hyperammonemia. Genetic analysis revealed that both girls were heterozygous for a novel missense mutation within exon 11 [c.1499A>T, p.(R443W)] of the GLUD1 gene. Despite early treatment with diazoxide and a low protein diet, they both developed non-hypoglycemic seizures in early childhood followed by cognitive impairment. In addition to their clinical course, a review of the literature on HI/HA syndrome is provided.
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Exones/genética , Glutamato Deshidrogenasa/genética , Hiperinsulinismo/genética , Hipoglucemia/genética , Mutación Missense/genética , Gemelos Monocigóticos/genética , Femenino , Humanos , Lactante , PronósticoRESUMEN
Lysosomal acid lipase deficiency is an autosomal recessive disorder with two distinct clinical phenotypes. Wolman disease is rapidly progressive with onset in early infancy. Complete enzyme deficiency results in massive accumulation of cholesterol esters and triglycerides in intestines, liver, spleen and other monocyte-macrophage system cells causing malabsorption, hepatosplenomegaly, liver failure and death in early infancy. Cholesterol ester storage disease may be diagnosed in childhood or later in life. It is characterized by chronic course and variable progression. Main features are variously expressed hepatopathy, including cirrhosis and liver failure, hypercholesterolemia and premature atherosclerosis. Characteristic is pathohistological finding of microvesicular steatosis and fibrosis and patognomonic are typical cholesterol ester crystals. Diagnosis is confirmed by enzyme assay and/or gene analysis. Until recently treatment was symptomatic. Ongoing clinical trials of enzyme replacement therapy have shown very promising results. We are presenting an infant with Wolman disease and two children with cholesterol ester storage disease with the aim to raise awareness about this disease and to start optimal care early.
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Enfermedad de Acumulación de Colesterol Éster/tratamiento farmacológico , Terapia de Reemplazo Enzimático , Enfermedad de Wolman/tratamiento farmacológico , Niño , Enfermedad de Acumulación de Colesterol Éster/complicaciones , Enfermedad de Acumulación de Colesterol Éster/diagnóstico , Humanos , Lactante , Enfermedad de Wolman/complicaciones , Enfermedad de Wolman/diagnóstico , Enfermedad de WolmanRESUMEN
OBJECTIVE: In this study, we report 5 patients with heterogeneous phenotypes and biochemical evidence of respiratory chain (RC) deficiency; however, the molecular diagnosis is not mitochondrial disease. METHODS: The reported patients were identified from a cohort of 60 patients in whom RC enzyme deficiency suggested mitochondrial disease and underwent whole-exome sequencing. RESULTS: Five patients had disease-causing variants in nonmitochondrial disease genes ORAI1, CAPN3, COLQ, EXOSC8, and ANO10, which would have been missed on targeted next-generation panels or on MitoExome analysis. CONCLUSIONS: Our data demonstrate that RC abnormalities may be secondary to various cellular processes, including calcium metabolism, neuromuscular transmission, and abnormal messenger RNA degradation.
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Three different genes of the glycosylphosphatidylinositol anchor synthesis pathway, PIGV, PIGO, and PGAP2, have recently been implicated in hyperphosphatasia-mental retardation syndrome (HPMRS), also known as Mabry syndrome, a rare autosomal recessive form of intellectual disability. The aim of this study was to delineate the PIGV mutation spectrum as well as the associated phenotypic spectrum in a cohort of 16 individuals diagnosed with HPMRS on the basis of intellectual disability and elevated serum alkaline phosphate as minimal diagnostic criteria. All PIGV exons and intronic boundaries were sequenced in 16 individuals. Biallelic PIGV mutations were identified in 8 of 16 unrelated families with HPMRS. The most frequent mutation detected in about 80% of affected families including the cases reported here is the c.1022C>A PIGV mutation, which was found in both the homozygous as well as the heterozygous state. Four further mutations found in this study (c. 176T>G, c.53G>A, c.905T>C, and c.1405C>T) are novel. Our findings in the largest reported cohort to date significantly extend the range of reported manifestations associated with PIGV mutations and demonstrate that the severe end of the clinical spectrum presents as a multiple congenital malformation syndrome with a high frequency of Hirschsprung disease, vesicoureteral, and renal anomalies as well as anorectal malformations. PIGV mutations are the major cause of HPMRS, which displays a broad clinical variability regarding associated malformations and growth patterns. Severe developmental delays, particular facial anomalies, brachytelephalangy, and hyperphosphatasia are consistently found in PIGV-positive individuals.
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Anomalías Múltiples/genética , Predisposición Genética a la Enfermedad/genética , Discapacidad Intelectual/genética , Manosiltransferasas/genética , Mutación , Trastornos del Metabolismo del Fósforo/genética , Anomalías Múltiples/patología , Adolescente , Secuencia de Aminoácidos , Preescolar , Estudios de Cohortes , Análisis Mutacional de ADN , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Discapacidad Intelectual/patología , Masculino , Datos de Secuencia Molecular , Fenotipo , Trastornos del Metabolismo del Fósforo/patología , Homología de Secuencia de Aminoácido , Síndrome , Adulto JovenRESUMEN
S-Adenosylhomocysteine hydrolase (AHCY) deficiency is a rare congenital disorder in methionine metabolism clinically characterized by white matter atrophy, delayed myelination, slowly progressive myopathy, retarded psychomotor development and mildly active chronic hepatitis. In the present study, we utilized a comparative proteomics strategy based on 2-DE/MALDI-MS and LC/ESI-MS to analyze plasma proteins from three AHCY-deficient patients prior to and after receiving dietary treatment designed to alleviate disease symptoms. Obtained results revealed candidate biomarkers for the detection of myopathy specifically associated with AHCY deficiency, such as carbonic anhydrase 3, creatine kinase, and thrombospondin 4. Several proteins mediating T-cell activation and function were identified as well, including attractin and diacylglycerol kinase α. Further validation and functional analysis of identified proteins with clinical value would ensure that these biomarkers make their way into routine diagnosis and management of AHCY deficiency.
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Adenosilhomocisteinasa/deficiencia , Proteínas Sanguíneas/análisis , Errores Innatos del Metabolismo/sangre , Adenosilhomocisteinasa/sangre , Biomarcadores/sangre , Biomarcadores/química , Proteínas Sanguíneas/química , Niño , Preescolar , Cromatografía Liquida , Electroforesis en Gel Bidimensional , Humanos , Lactante , Masculino , Errores Innatos del Metabolismo/enzimología , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
S-adenosylhomocysteine hydrolase (AdoHcyase) catalyzes the hydrolysis of AdoHcy to adenosine and homocysteine. Increased levels of AdoHcy may play a role in the development of cardiovascular diseases and numerous other conditions associated with hyperhomocysteinemia. Several polymorphic isoforms named SAHH-1 to 4 may be resolved by horizontal starch gel electrophoresis from red blood cells. We have identified the genetic background of isoforms SAHH-2 and SAHH-3. SAHH-2 represents the previously described polymorphism in exon 2 of the AdoHcyase gene (112 C>T; p.R38W). Isoform SAHH-3 is based on a new polymorphism in exon 3 (377 G>A), leading to the conversion of glycine to arginine at amino-acid position 123. To shed light on the effects of these polymorphisms on the molecular and catalytic properties of AdoHcyase, we made recombinant wild-type and polymorphic R38W and G123R enzymes for a comparative analysis. The amino-acid exchanges did not bring about major changes to the catalytic rates of the recombinant proteins. However, circular dichroism analysis showed that both polymorphisms effect the thermal stability of the recombinant protein in vitro, reducing the unfolding temperature by approximately 2.6 degrees C (R38W) and 1.5 degrees C (G123R) compared to wild-type protein. In view of the altered thermal stability, and slightly decreased enzymatic activity of polymorphic proteins (< or =6%), one may consider the analyzed AdoHcyase isoforms as risk markers for diseases caused by irregular AdoHcyase metabolism.
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Adenosilhomocisteinasa/fisiología , Sustitución de Aminoácidos , Adenosilhomocisteinasa/química , Adenosilhomocisteinasa/genética , Dicroismo Circular , Estabilidad de Enzimas/genética , Calor , Humanos , Isoenzimas/genéticaRESUMEN
Recently, we have described the first human case of AdoHcyase (S-adenosylhomocysteine hydrolase) deficiency. Two point mutations in the AdoHcyase gene, the missense mutation p.Y143C (AdoHcyase in which Tyr143 is replaced by cysteine) and the truncation mutation p.W112stop (AdoHcyase in which Trp112 is replaced by opal stop codon) were identified [Baric, Fumic, Glenn, Cuk, Schulze, Finkelstein, James, Mejaski-Bosnjak, Pazanin, Pogribny et al. (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 4234-4239]. To elucidate the molecular and catalytic properties of AdoHcyase, we have made recombinant wild-type and mutant p.Y143C (AdoHcyase in which Tyr143 is replaced by cysteine) enzymes for a comparative analysis. The catalytic rates of p.Y143C protein in the directions of S-adenosylhomocysteine synthesis or hydrolysis are decreased from 65% to 75%. Further, the oxidation states of coenzyme NAD differ between mutant and wild-type protein, with an increased NADH accumulation in the mutant p.Y143C enzyme of 88% NADH (wild-type contains 18% NADH). Quantitative binding of NAD is not affected. Native polyacrylamide gel electrophoresis showed, that mutant p.Y143C subunits are able to form the tetrameric complex as is the wild-type enzyme. CD analysis showed that the p.Y143C mutation renders the recombinant protein thermosensitive, with an unfolding temperature significantly reduced by 7 degrees C compared with wild-type protein. Change of Glu115 to lysine in wild-type protein causes a change in thermosensitivity almost identical with that found in the p.Y143C enzyme, indicating that the thermosensitivity is due to a missing hydrogen bond between Tyr143 and Glu115. We emphasize involvement of this particular hydrogen bond for subunit folding and/or holoenyzme stability. In summary, a single mutation in the AdoHcyase affecting both the oxidation state of bound co-factor NAD and enzyme stability is present in a human with AdoHcyase deficiency.
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Adenosilhomocisteinasa/genética , Adenosilhomocisteinasa/metabolismo , Mutación , NAD/metabolismo , Adenosilhomocisteinasa/química , Sustitución de Aminoácidos , Catálisis , Cisteína/genética , Cisteína/metabolismo , Ditiotreitol/farmacología , Estabilidad de Enzimas , Escherichia coli/genética , Calor , Humanos , Enlace de Hidrógeno , Hidrólisis , Cinética , Modelos Moleculares , Mutagénesis Sitio-Dirigida , NAD/química , Oxidación-Reducción , Pliegue de Proteína , Estructura Cuaternaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sustancias Reductoras/farmacología , Relación Estructura-Actividad , Tirosina/genética , Tirosina/metabolismoRESUMEN
We report studies of a Croatian boy, a proven case of human S-adenosylhomocysteine (AdoHcy) hydrolase deficiency. Psychomotor development was slow until his fifth month; thereafter, virtually absent until treatment was started. He had marked hypotonia with elevated serum creatine kinase and transaminases, prolonged prothrombin time and low albumin. Electron microscopy of muscle showed numerous abnormal myelin figures; liver biopsy showed mild hepatitis with sparse rough endoplasmic reticulum. Brain MRI at 12.7 months revealed white matter atrophy and abnormally slow myelination. Hypermethioninemia was present in the initial metabolic study at age 8 months, and persisted (up to 784 microM) without tyrosine elevation. Plasma total homocysteine was very slightly elevated for an infant to 14.5-15.9 microM. In plasma, S-adenosylmethionine was 30-fold and AdoHcy 150-fold elevated. Activity of AdoHcy hydrolase was approximately equal to 3% of control in liver and was 5-10% of the control values in red blood cells and cultured fibroblasts. We found no evidence of a soluble inhibitor of the enzyme in extracts of the patient's cultured fibroblasts. Additional pretreatment abnormalities in plasma included low concentrations of phosphatidylcholine and choline, with elevations of guanidinoacetate, betaine, dimethylglycine, and cystathionine. Leukocyte DNA was hypermethylated. Gene analysis revealed two mutations in exon 4: a maternally derived stop codon, and a paternally derived missense mutation. We discuss reasons for biochemical abnormalities and pathophysiological aspects of AdoHcy hydrolase deficiency.
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Adenosilhomocisteinasa/deficiencia , Enfermedades Genéticas Congénitas/fisiopatología , Metionina/metabolismo , Adenosilhomocisteinasa/genética , Encéfalo/diagnóstico por imagen , Enfermedades Genéticas Congénitas/dietoterapia , Humanos , Lactante , Recién Nacido , Hígado/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Metionina/sangre , Radiografía , UltrasonografíaRESUMEN
Conventional cytogenetics detected an interstitial deletion of proximal region of p-arm of chromosome 2 in a 6-month-old boy with a phenotype slightly resembling Down's syndrome. The deletion was inherited from the father, whose karyotype revealed a small ring-shaped marker chromosome, in addition to interstitial deletion. Fluorescence in situ hybridization identified the marker, which consisted of the proximal region of the p-arm of chromosome 2, including a part of its centromere. This case shows that molecular cytogenetic analysis can reveal the mechanism of the formation of the marker chromosome.
Asunto(s)
Aberraciones Cromosómicas , Cromosomas Humanos Par 2/ultraestructura , Cromosomas en Anillo , Análisis Citogenético , Marcadores Genéticos/genética , Humanos , Hibridación Fluorescente in Situ , Lactante , Cariotipificación , Masculino , Sensibilidad y EspecificidadRESUMEN
AIM: To estimate the exposure of Zagreb University medical students to psychoactive substances in 2000 and compare it with data collected in 1989. METHODS: Students were surveyed in 2000 (n=775) and 1989 (n=986) by means of a self-reporting questionnaire. The 2000 survey also included 136 non-medical students. General demographic data and data on experience with psychoactive substances were collected, analyzed, and presented as percentages with 95% CI. RESULTS: The lifetime prevalence of contact with illicit drugs (mostly marijuana) among medical students in 2000 was 35% vs 14% in 1989. Repeated use was reported by 3.9% students, and 6% confirmed the experience of simultaneous use of alcohol and drugs. The lifetime prevalence of contact with psychoactive medications (mostly benzodiazepines) was 33% in 2000 vs 15% in 1989. Medications were largely used without medical supervision, with 3.5% of the students explicitly stating non-medical reasons for consumption. The prevalence of smokers was 29% in 2000, compared with 31% in 1989, and prevalence of regular alcohol consumers (on monthly, weekly, or daily basis) was 50% vs 52% in 1989. Experience with all types of substances was more present among senior students, and less among medical students than their "non-medical" peers. Regular alcohol use was associated with the experience of illicit drugs use. In 2000, 40% of medical students and 53% of "non-medical" students voted for legalization of marijuana. CONCLUSIONS: Experience with psychoactive substances is common among Zagreb medical students. Experiences with illicit drugs and psychoactive medications have substantially increased over the past decade.
Asunto(s)
Estudiantes de Medicina/estadística & datos numéricos , Trastornos Relacionados con Sustancias/epidemiología , Consumo de Bebidas Alcohólicas/epidemiología , Croacia/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , Fumar/epidemiologíaRESUMEN
AIM: To determine students opinions about diagnosis disclosure to the patient and other interested parties. METHODS: During 2000/2001 academic year, an anonymous survey was conducted among the first-year (200 questionnaires) and sixth-year medical students (200 questionnaires) at the Zagreb University School of Medicine. Students were asked what they would say about the diagnosis to the patient, patients family, friend, employer, colleague from work, health insurance agent, another physician, or medical student, if the diagnosis was inoperable lung carcinoma in a 20- and 66-year-old patient vs bacterial pneumonia in patients of the same age. The possibilities were to tell the truth, lie, or refuse to disclose the diagnosis. RESULTS: The response rate was 55%. Students would disclose the true diagnosis to the patient, patients family, friend, and employer in case of benign disease more often than in case of malignant disease (p<0.001). Patient's age did not affect students' opinions. Most students would rather refuse to say anything than lie if they would not want to say the truth. Students would more often tell the truth to the patient and patient's family then to a health insurance agent, another physician, or medical student, less often to patient's friend and employer, and rarely to the patient's colleague from work. First-year students would generally tell the truth more often than sixth-year students (p<0.001). There were almost no differences in the opinions between male and female students. CONCLUSION: The strongest influence on students choice on whether or not to disclose the diagnosis had the severity of disease, person they would disclose the information to, and the academic year they attended, implicating that such important ethical issues should be discussed during the studies.