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1.
Nat Genet ; 11(3): 335-7, 1995 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7581461

RESUMO

Spinal muscular atrophy (SMA) is a frequent autosomal recessive disease characterized by degeneration of the motor neurons of the spinal cord causing proximal paralysis with muscle atrophy. The region on chromosome 5q13 encompassing the disease gene is particularly unstable and prone to large-scale deletions whose characterization recently led to the identification of the survival motor neuron (SMN) gene. We now present a genetic analysis of 54 unrelated Spanish SMA families that has revealed a 4-basepair (bp) deletion (AGAG) in exon 3 of SMN in four unrelated patients. This deletion, which results in a frameshift and a premature stop codon, occurs on the same haplotype background, suggesting that a single mutational event is involved in the four families. The other patients showed either deletions of the SMN gene (49/54) or a gene conversion event changing SMN exon 7 into its highly homologous copy (cBCD541, 1/54). This observation gives strong support to the view that mutations of the SMN gene are responsible for the SMA phenotype as it is the first frameshift mutation reported in SMA.


Assuntos
Mutação da Fase de Leitura , Atrofia Muscular Espinal/genética , Proteínas do Tecido Nervoso/genética , Deleção de Sequência , Sequência de Bases , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Conversão Gênica , Humanos , Dados de Sequência Molecular , Atrofia Muscular Espinal/classificação , Linhagem , Polimorfismo Conformacional de Fita Simples , Proteínas de Ligação a RNA , Proteínas do Complexo SMN , Análise de Sequência de DNA , Espanha
2.
Nat Genet ; 26(4): 480-3, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11101850

RESUMO

Schwartz-Jampel syndrome (SJS1) is a rare autosomal recessive disorder characterized by permanent myotonia (prolonged failure of muscle relaxation) and skeletal dysplasia, resulting in reduced stature, kyphoscoliosis, bowing of the diaphyses and irregular epiphyses. Electromyographic investigations reveal repetitive muscle discharges, which may originate from both neurogenic and myogenic alterations. We previously localized the SJS1 locus to chromosome 1p34-p36.1 and found no evidence of genetic heterogeneity. Here we describe mutations, including missense and splicing mutations, of the gene encoding perlecan (HSPG2) in three SJS1 families. In so doing, we have identified the first human mutations in HSPG2, which underscore the importance of perlecan not only in maintaining cartilage integrity but also in regulating muscle excitability.


Assuntos
Proteoglicanas de Heparan Sulfato/genética , Mutação , Osteocondrodisplasias/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Mapeamento Cromossômico , Análise Mutacional de DNA , Primers do DNA/genética , Feminino , Proteoglicanas de Heparan Sulfato/química , Humanos , Masculino , Camundongos , Dados de Sequência Molecular , Linhagem , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Especificidade da Espécie
3.
Nat Genet ; 21(3): 285-8, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10080180

RESUMO

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by early contractures of elbows and Achilles tendons, slowly progressive muscle wasting and weakness, and a cardiomyopathy with conduction blocks which is life-threatening. Two modes of inheritance exist, X-linked (OMIM 310300) and autosomal dominant (EDMD-AD; OMIM 181350). EDMD-AD is clinically identical to the X-linked forms of the disease. Mutations in EMD, the gene encoding emerin, are responsible for the X-linked form. We have mapped the locus for EDMD-AD to an 8-cM interval on chromosome 1q11-q23 in a large French pedigree, and found that the EMD phenotype in four other small families was potentially linked to this locus. This region contains the lamin A/C gene (LMNA), a candidate gene encoding two proteins of the nuclear lamina, lamins A and C, produced by alternative splicing. We identified four mutations in LMNA that co-segregate with the disease phenotype in the five families: one nonsense mutation and three missense mutations. These results are the first identification of mutations in a component of the nuclear lamina as a cause of inherited muscle disorder. Together with mutations in EMD (refs 5,6), they underscore the potential importance of the nuclear envelope components in the pathogenesis of neuromuscular disorders.


Assuntos
Distrofias Musculares/genética , Mutação , Proteínas Nucleares/genética , Sequência de Aminoácidos , Clonagem Molecular , Desoxirribonuclease HpaII/genética , Desoxirribonucleases de Sítio Específico do Tipo II/genética , Éxons , Feminino , Genes Dominantes , Haplótipos , Humanos , Imuno-Histoquímica , Lamina Tipo A , Laminas , Masculino , Repetições de Microssatélites , Dados de Sequência Molecular , Distrofia Muscular de Emery-Dreifuss , Miocárdio/metabolismo , Miocárdio/patologia , Proteínas Nucleares/análise , Proteínas Nucleares/metabolismo , Linhagem , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
4.
Nat Genet ; 20(1): 31-6, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9731526

RESUMO

Miyoshi myopathy (MM) is an adult onset, recessive inherited distal muscular dystrophy that we have mapped to human chromosome 2p13. We recently constructed a 3-Mb P1-derived artificial chromosome (PAC) contig spanning the MM candidate region. This clarified the order of genetic markers across the MM locus, provided five new polymorphic markers within it and narrowed the locus to approximately 2 Mb. Five skeletal muscle expressed sequence tags (ESTs) map in this region. We report that one of these is located in a novel, full-length 6.9-kb muscle cDNA, and we designate the corresponding protein 'dysferlin'. We describe nine mutations in the dysferlin gene in nine families; five are predicted to prevent dysferlin expression. Identical mutations in the dysferlin gene can produce more than one myopathy phenotype (MM, limb girdle dystrophy, distal myopathy with anterior tibial onset).


Assuntos
Proteínas de Membrana , Proteínas Musculares/genética , Distrofias Musculares/genética , Mutação , Adulto , Sequência de Aminoácidos , Northern Blotting , Clonagem Molecular , Disferlina , Feminino , Expressão Gênica , Marcadores Genéticos , Humanos , Masculino , Dados de Sequência Molecular , Proteínas Musculares/química , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Polimorfismo Genético , Polimorfismo Conformacional de Fita Simples
5.
J Neuromuscul Dis ; 8(4): 633-645, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33749658

RESUMO

BACKGROUND: Dominant and recessive autosomal pathogenic variants in the three major genes (COL6A1-A2-A3) encoding the extracellular matrix protein collagen VI underlie a group of myopathies ranging from early-onset severe conditions (Ullrich congenital muscular dystrophy) to milder forms maintaining independent ambulation (Bethlem myopathy). Diagnosis is based on the combination of clinical presentation, muscle MRI, muscle biopsy, analysis of collagen VI secretion, and COL6A1-A2-A3 genetic analysis, the interpretation of which can be challenging. OBJECTIVE: To refine the phenotypical spectrum associated with the frequent COL6A3 missense variant c.7447A>G (p.Lys2483Glu). METHODS: We report the clinical and molecular findings in 16 patients: 12 patients carrying this variant in compound heterozygosity with another COL6A3 variant, and four homozygous patients. RESULTS: Patients carrying this variant in compound heterozygosity with a truncating COL6A3 variant exhibit a phenotype consistent with COL6-related myopathies (COL6-RM), with joint contractures, proximal weakness and skin abnormalities. All remain ambulant in adulthood and only three have mild respiratory involvement. Most show typical muscle MRI findings. In five patients, reduced collagen VI secretion was observed in skin fibroblasts cultures. All tested parents were unaffected heterozygous carriers. Conversely, two out of four homozygous patients did not present with the classical COL6-RM clinical and imaging findings. Collagen VI immunolabelling on cultured fibroblasts revealed rather normal secretion in one and reduced secretion in another. Muscle biopsy from one homozygous patient showed myofibrillar disorganization and rimmed vacuoles. CONCLUSIONS: In light of our results, we postulate that the COL6A3 variant c.7447A>G may act as a modulator of the clinical phenotype. Thus, in patients with a typical COL6-RM phenotype, a second variant must be thoroughly searched for, while for patients with atypical phenotypes further investigations should be conducted to exclude alternative causes. This works expands the clinical and molecular spectrum of COLVI-related myopathies.


Assuntos
Colágeno Tipo VI/genética , Distrofias Musculares/genética , Pró-Colágeno/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Heterozigoto , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/patologia , Doenças Musculares/genética , Mutação , Fenótipo , Adulto Jovem
6.
Muscle Nerve ; 41(1): 133-7, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19768756

RESUMO

Pyridostigmine relieved episodic weakness in a family with paramyotonia congenita resulting from the R1448C mutation in the sodium channel gene. The transmission was autosomal dominant and the patients had paradoxical myotonia and exercise-induced weakness. On electrophysiological studies there were myotonic potentials, and there was progressive reduction of compound muscle action potential (CMAP) amplitudes after short exercise associated with clinical weakness. Pyridostigmine in doses of 60 mg three times daily abolished the drop in the postexercise CMAP amplitude and reduced the amplitude decrement to slow rate repetitive stimulation, but there continued to be a drop in amplitude on exposure to cold. The decline of the CMAP amplitude on exposure to cold was controlled by treatment with phenytoin. The clinical and electrophysiological features are discussed in relation to therapy with pyridostigmine and phenytoin.


Assuntos
Debilidade Muscular/tratamento farmacológico , Transtornos Miotônicos/complicações , Brometo de Piridostigmina/uso terapêutico , Adulto , Inibidores da Colinesterase/uso terapêutico , Eletromiografia , Feminino , Seguimentos , Humanos , Debilidade Muscular/etiologia , Debilidade Muscular/fisiopatologia , Transtornos Miotônicos/tratamento farmacológico , Transtornos Miotônicos/fisiopatologia , Linhagem
7.
Eur J Neurol ; 17(1): 160-2, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19538222

RESUMO

BACKGROUND AND PURPOSE: Spinal muscular atrophy (SMA) is a common autosomal recessive neuromuscular disorder. Carrier frequency studies of SMA have been reported for various populations. Although no large-scale population-based studies of SMA have been performed in Iran, previous estimates have indicated that the incidence of autosomal recessive disorder partly because of the high prevalence of consanguineous marriage is much higher in the Iranian population than in other populations. METHODS: In this study, we used a reliable and highly sensitive quantitative real-time PCR assay with SYBR green I dye to detect the copy number of the SMN1 gene to determine the carrier frequency of SMA in 200 healthy unrelated, non-consanguineous couples from different part of Iran. RESULTS: To validate the method in our samples, we determined the relative quantification (RQ) of patients with homozygous deletion (0.00) and hemyzygous carriers (0.29-0.55). The RQ in 10 of 200 normal individuals were within the carrier range of 0.31-0.57, estimating a carrier frequency of 5% in the Iranian population. CONCLUSIONS: Our data show that the SMA carrier frequency in Iran is higher than in the European population and that further programs of population carrier detection and prenatal testing should be implemented.


Assuntos
Deleção de Genes , Triagem de Portadores Genéticos/métodos , Heterozigoto , Atrofia Muscular Espinal/genética , Mutação/genética , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Adulto , Criança , Análise Mutacional de DNA , Feminino , Frequência do Gene/genética , Marcadores Genéticos/genética , Testes Genéticos/normas , Genótipo , Humanos , Irã (Geográfico)/etnologia , Masculino , Atrofia Muscular Espinal/diagnóstico , Atrofia Muscular Espinal/etnologia , Programas Nacionais de Saúde , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos
8.
Neurologia (Engl Ed) ; 35(3): 185-206, 2020 Apr.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-31003788

RESUMO

BACKGROUND AND OBJECTIVES: Steinert's disease or myotonic dystrophy type 1 (MD1), (OMIM 160900), is the most prevalent myopathy in adults. It is a multisystemic disorder with dysfunction of virtually all organs and tissues and a great phenotypical variability, which implies that it has to be addressed by different specialities with experience in the disease. The knowledge of the disease and its management has changed dramatically in recent years. This guide tries to establish recommendations for the diagnosis, prognosis, follow-up and treatment of the complications of MD1. MATERIAL AND METHODS: Consensus guide developed through a multidisciplinary approach with a systematic literature review. Neurologists, pulmonologists, cardiologists, endocrinologists, neuropaediatricians and geneticists have participated in the guide. RECOMMENDATIONS: The genetic diagnosis should quantify the number of CTG repetitions. MD1 patients need cardiac and respiratory lifetime follow-up. Before any surgery under general anaesthesia, a respiratory evaluation must be done. Dysphagia must be screened periodically. Genetic counselling must be offered to patients and relatives. CONCLUSION: MD1 is a multisystemic disease that requires specialised multidisciplinary follow-up.


Assuntos
Aconselhamento Genético , Distrofia Miotônica/diagnóstico , Distrofia Miotônica/genética , Guias de Prática Clínica como Assunto/normas , Transtornos de Deglutição , Seguimentos , Humanos , Distrofia Miotônica/complicações
9.
J Neurol Sci ; 406: 116376, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31634715

RESUMO

The autosomal recessive demyelinating form of Charcot-Marie-Tooth can be due to SH3TC2 gene pathogenic variants (CMT4C, AR-CMTde-SH3TC2). We report on a series of 13 patients with AR-CMTde-SH3TC2 among a French cohort of 350 patients suffering from all type of inheritance peripheral neuropathy. The SH3TC2 gene appeared to be the most frequently mutated gene for demyelinating neuropathy in this series by NGS. Four new pathogenic variants have been identified: two nonsense variants (p.(Tyr970*), p.(Trp1199*)) and two missense variants (p.(Leu1126Pro), p.(Ala1206Asp)). The recurrent variant p.Arg954* was present in 62%, and seems to be a founder mutation. The phenotype is fairly homogeneous, as all these patients, except the youngest ones, presented scoliosis and/or hearing loss.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Surdez/genética , Variação Genética/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Escoliose/genética , Adulto , Idoso , Doença de Charcot-Marie-Tooth/epidemiologia , Criança , Estudos de Coortes , Surdez/epidemiologia , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação/genética , Escoliose/epidemiologia , Adulto Jovem
10.
Neuromuscul Disord ; 16(4): 277-81, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16531045

RESUMO

We report the observation of an 18-year-old girl, whose clinical presentation was very suggestive of a congenital myopathy with neonatal onset. A congenital myopathy had been already diagnosed in her brother and in addition her half-cousin died diagnosed with a severe nemaline myopathy at age 4 years. A muscle biopsy performed on both siblings revealed histological and ultrastructural features of 'cap myopathy'. This case report suggests that 'cap myopathy' and some cases of nemaline myopathy with neonatal onset might be two phenotypic expressions of the same genetic disorder. These two entities could therefore, perhaps, be regarded as 'Z-line disorders' possibly caused by defective myofibrillogenesis.


Assuntos
Doenças Musculares/congênito , Doenças Musculares/genética , Miopatias da Nemalina/diagnóstico , Miopatias da Nemalina/genética , Actinas/genética , Adolescente , Adulto , Biópsia , Pré-Escolar , Feminino , Humanos , Masculino , Músculos/patologia , Doenças Musculares/diagnóstico , Mutação , Cadeias Pesadas de Miosina/genética , Linhagem
12.
Brain ; 128(Pt 4): 732-42, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15689361

RESUMO

We present here the clinical, molecular and biochemical findings from 238 limb-girdle muscular dystrophy type 2A (LGMD2A) patients, representing approximately 50% (238 out of 484) of the suspected calpainopathy cases referred for the molecular study of the calpain 3 (CAPN3) gene. The mean age at onset of LGMD2A patients was approximately 14 years, and the first symptoms occurred between 6 and 18 years of age in 71% of patients. The mean age at which the patients became wheelchair bound was 32.2 years, with 84% requiring the use of a wheelchair between the age of 21 and 40 years. There was no correlation between the age at onset and the time at which the patient became wheelchair bound, nor between the sex of the patient and the risk of becoming wheelchair bound. Of the cases where the CAPN3 gene was not affected, approximately 20% were diagnosed as LGMD2I muscular dystrophy, while facioscapulohumeral muscular dystrophy (FSHD) was uncommon in this sample. We identified 105 different mutations in the CAPN3 gene of which 50 have not been described previously. These were distributed throughout the coding region of the gene, although some exons remained free of mutations. The most frequent mutation was 2362AG-->TCATCT (exon 22), which was present in 30.7% of the chromosomes analysed (146 chromosomes). Other recurrent mutations described were N50S, 550DeltaA, G222R, IVS6-1G-->A, A483D, IVS17+1G-->T, 2069-2070DeltaAC, R748Q and R748X, each of which was found in >5 chromosomes. The type of mutation in the CAPN3 gene does not appear to be a risk factor for becoming dependent on a wheelchair at a determined age. However, in the cases with two null mutations, there were significantly fewer patients that were able to walk than in the group of patients with at least one missense mutation. Despite the fact that the results of phenotyping and western blot might be biased due to multiple referral centres, producing a diagnosis on the basis of the classical phenotype is neither sufficiently sensitive (86.7%) nor specific (69.3%), although western blot proved to be even less sensitive (52.5%) yet more specific (87.8%). In this case LGMD2I was a relevant cause of false-positive diagnoses. Considering both the clinical phenotype and the biochemical information together, the probability of correctly diagnosing a calpainopathy is very high (90.8%). However, if one of the analyses is lacking, the probability varies from 78.3 to 73.7% depending on the information available. When both tests are negative, the probability that the sample comes from a patient with LGMD2A was 12.2%.


Assuntos
Calpaína/genética , Isoenzimas/genética , Proteínas Musculares/genética , Distrofia Muscular do Cíngulo dos Membros/genética , Adolescente , Adulto , Idade de Início , Teorema de Bayes , Western Blotting , Criança , Análise Mutacional de DNA/métodos , Progressão da Doença , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Distrofia Muscular do Cíngulo dos Membros/diagnóstico , Distrofia Muscular do Cíngulo dos Membros/epidemiologia , Mutação de Sentido Incorreto , Fenótipo , Estudos Retrospectivos
13.
J Med Genet ; 37(5): 361-7, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10807695

RESUMO

Limb-girdle muscular dystrophies constitute a broad range of clinical and genetic entities. We have evaluated 38 autosomal recessive limb-girdle muscular dystrophy (LGMD2) families by linkage analysis for the known loci of LGMD2A-F and protein studies using immunofluorescence and western blotting of the sarcoglycan complex. One index case in each family was investigated thoroughly. The age of onset and the current ages were between 11/2 and 15 years and 6 and 36 years, respectively. The classification of families was as follows: calpainopathy 7, dysferlinopathy 3, alpha sarcoglycan deficiency 2, beta sarcoglycan deficiency 7, gamma sarcoglycan deficiency 5, delta sarcoglycan deficiency 1, and merosinopathy 2. There were two families showing an Emery-Dreifuss phenotype and nine showing no linkage to the LGMD2A-F loci, and they had preserved sarcoglycans. gamma sarcoglycan deficiency seems to be the most severe group as a whole, whereas dysferlinopathy is the mildest. Interfamilial variation was not uncommon. Cardiomyopathy was not present in any of the families. In sarcoglycan deficiencies, sarcoglycans other than the primary ones may also be considerably reduced; however, this may not be reflected in the phenotype. Many cases of primary gamma sarcoglycan deficiency showed normal or only mildly abnormal delta sarcoglycan staining.


Assuntos
Genes Recessivos , Ligação Genética , Distrofias Musculares/genética , Adolescente , Adulto , Western Blotting , Criança , Pré-Escolar , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Feminino , Imunofluorescência , Humanos , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Distrofias Musculares/classificação , Distrofias Musculares/patologia
14.
Acta Myol ; 24(2): 78-9, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16550920

RESUMO

Muscle weakness associated to marked joint deformities is not an uncommon clinical situation in daily neuromuscular clinics. These abnormalities encompass a large variety of conditions including non-primary muscle disorders. Besides well-defined and rather readily recognisable hereditary syndromes such as Bethlem myopathy or Ullrich congenital muscular dystrophy, some unusual etiologies should also be considered. We report here two paradigmatic cases in which we found mutations in two novel genes corresponding to two newly described entities (progressive pseudorheumatoid dysplasia, PPD, and infantile systemic hyalinosis, ISH) both conditions in which the clinical picture can mimick primary muscle disease.


Assuntos
Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Deformidades Articulares Adquiridas/genética , Debilidade Muscular/genética , Proteínas de Neoplasias/genética , Proteínas de Sinalização Intercelular CCN , Criança , Evolução Fatal , Humanos , Masculino , Debilidade Muscular/epidemiologia
15.
Eur J Hum Genet ; 6(4): 396-9, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9781048

RESUMO

Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive muscular dystrophy with primary gamma-sarcoglycan deficiency, generally associated with a severe clinical course. gamma-sarcoglycan, a 35kDa dystrophin-associated protein, is encoded by a single gene on chromosome 13q12. Six different mutations have been described in that gene, and it has been proved they are the origin of the disease. One of these mutations (C283Y), a G-->A transition in codon 283, was recently and exclusively identified in Gypsy patients from different European countries. We report the study of 11 LGMD2C unrelated Gypsy families (nine Spanish and two Portugese). The muscle biopsies of these patients showed a drastically decreased immunostaining with alpha and gamma-sarcoglycan antibodies. All the patients were homozygous for C283Y missense mutation, and all affected chromosomes (patients and heterozygous relatives) carried the allele 5 (112 bp) of the intragenic microsatellite D13S232. Unexpectedly, this allele is most frequent in the Caucasian population but not in the normal Gypsy population. The clinical severity of all patients demonstrates that the C283Y missense mutation in a homozygous state causes a severe LGMD2C (DMD-like). The elevated number of families ascertained let us assume that LGMD2C is prevalent in the Gypsy population, and that all the families have inherited a founding mutation.


Assuntos
Proteínas do Citoesqueleto/genética , Efeito Fundador , Glicoproteínas de Membrana/genética , Distrofias Musculares/genética , Mutação de Sentido Incorreto , Roma (Grupo Étnico) , Consanguinidade , Extremidades , Feminino , Genética Populacional , Homozigoto , Humanos , Masculino , Distrofias Musculares/etnologia , Linhagem , Fenótipo , Sarcoglicanas
16.
Neurology ; 57(2): 271-8, 2001 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-11468312

RESUMO

OBJECTIVE: Mutations in the skeletal muscle gene dysferlin cause two autosomal recessive forms of muscular dystrophy: Miyoshi myopathy (MM) and limb girdle muscular dystrophy type 2B (LGMD2B). The purpose of this study was to define the genomic organization of the dysferlin gene and conduct mutational screening and a survey of clinical features in 21 patients with defined molecular defects in the dysferlin gene. METHODS: Genomic organization of the gene was determined by comparing the dysferlin cDNA and genomic sequence in P1-derived artificial chromosomes (PACs) containing the gene. Mutational screening entailed conformational analysis and sequencing of genomic DNA and cDNA. Clinical records of patients with defined dysferlin gene defects were reviewed retrospectively. RESULTS: The dysferlin gene encompasses 55 exons spanning over 150 kb of genomic DNA. Mutational screening revealed nine novel mutations associated with MM. The range of onset in this patient group was narrow with a mean of 19.0 +/- 3.9 years. CONCLUSION: This study confirms that the dysferlin gene is mutated in MM and LGMD2B and extends understanding of the timing of onset of the disease. Knowledge of the genomic organization of the gene will facilitate mutation detection and investigations of the molecular biologic properties of the dysferlin gene.


Assuntos
Proteínas de Membrana , Proteínas Musculares/genética , Distrofias Musculares/genética , Mutação/genética , Adolescente , Adulto , Criança , Mapeamento Cromossômico , Disferlina , Éxons , Feminino , Genótipo , Humanos , Íntrons , Masculino , Polimorfismo Conformacional de Fita Simples
17.
Neuromuscul Disord ; 11(5): 494-8, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11404124

RESUMO

We report a 6-year-old female patient presenting with a sudden and severe single episode of rhabdomyolysis in which screening for a metabolic disorder was negative. Four months after the episode a muscle biopsy was performed and showed a mild pattern of necrosis/regeneration. Upon immunofluorescence, a mosaic pattern of dystrophin deficiency was found, and in the dystrophin deficient muscle fibres, the four proteins of the sarcoglycan complex were also lacking. Genetic analysis showed a duplication of exons 3 to 17 on one X-chromosome of the proband, but not on the mother's X-chromosome. A clearly skewed X-inactivation (85% of the defective X being active) was found and is consistent with the patient being symptomatic. To our knowledge, a spontaneous rhabdomyolysis in a female Duchenne muscular dystrophy carrier has never been reported.


Assuntos
Mecanismo Genético de Compensação de Dose , Distrofina/genética , Genes Duplicados , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patologia , Biópsia , Criança , Feminino , Heterozigoto , Humanos , Distrofia Muscular de Duchenne/metabolismo , Rabdomiólise/genética , Rabdomiólise/metabolismo , Rabdomiólise/patologia , Cromossomo X
18.
Neuromuscul Disord ; 10(1): 10-5, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10677858

RESUMO

We describe a six generation Saudi kindred, with a recessive hereditary motor and sensory neuropathy (HMSN). Four individuals were affected including two children (a boy and a girl) and a 23-year-old man. The fourth (a female) died at the age of 14 years. Onset of the disease was early (< 2 years) and the clinical and neurophysiological features were, generally, quite similar to those of an Italian family linked to chromosome 11q23. The peculiar pathologic pattern was irregular and redundant loops associated with folding of the myelin sheaths. The genetic study confirmed linkage to chromosome 11q23 and refined the location of the gene between D11S1311 and D11S917, a 3.3 cM region. These findings support the existence of a homogeneous and distinct entity within the form of HMSN associated with focally folded myelin sheaths.


Assuntos
Cromossomos Humanos Par 11 , Genes Recessivos , Ligação Genética , Neuropatia Hereditária Motora e Sensorial/genética , Neuropatia Hereditária Motora e Sensorial/patologia , Bainha de Mielina/patologia , Adulto , Pré-Escolar , Feminino , Genótipo , Neuropatia Hereditária Motora e Sensorial/fisiopatologia , Humanos , Masculino , Microscopia Eletrônica , Sistema Nervoso/patologia , Sistema Nervoso/fisiopatologia , Linhagem , Nervo Sural/patologia
19.
Neuromuscul Disord ; 10(8): 584-91, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11053686

RESUMO

Hereditary motor and sensory neuropathy type Lom, initially identified in Roma (Gypsy) families from Bulgaria, has been mapped to 8q24. Further refined mapping of the region has been undertaken on DNA from patients diagnosed across Europe. The refined map consists of 25 microsatellite markers over approximately 3 cM. In this collaborative study we have identified a number of historical recombinations resulting from the spread of the hereditary motor and sensory neuropathy type Lom gene through Europe with the migration and isolation of Gypsy groups. Recombination mapping and the minimal region of homozygosity reduced the original 3 cM hereditary motor and sensory neuropathy type Lom region to a critical interval of about 200 kb.


Assuntos
Neuropatia Hereditária Motora e Sensorial/genética , Adolescente , Adulto , Criança , Mapeamento Cromossômico , Análise Mutacional de DNA , Progressão da Doença , Europa (Continente) , Feminino , Genótipo , Haplótipos/genética , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Roma (Grupo Étnico)/genética
20.
Neuromuscul Disord ; 9(8): 564-72, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10619714

RESUMO

Autosomal recessive nemaline (rod) myopathy is clinically and genetically heterogeneous. A clinically distinct, typical form, with onset in infancy and a non-progressive or slowly progressive course, has been assigned to a region on chromosome 2q22 harbouring the nebulin gene Mutations have now been found in this gene, confirming its causative role. The gene for slow tropomyosin TPM3 on chromosome 1q21, previously found to cause a dominantly inherited form, has recently been found to be homozygously mutated in one severe consanguineous case. Here we wished to determine the degree of genetic homogeneity or heterogeneity of autosomal recessive nemaline myopathy by linkage analysis of 45 families from 10 countries. Forty-one of the families showed linkage results compatible with linkage to markers in the nebulin region, the highest combined lod scores at zero recombination being 14.13 for the marker D2S2236. We found no indication of genetic heterogeneity for the typical form of nemaline myopathy. In four families with more severe forms of nemaline myopathy, however, linkage to both the nebulin and the TPM3 locus was excluded. Our results indicate that at least three genetic loci exist for autosomal recessive nemaline myopathy. Studies of additional families are needed to localise the as yet unknown causative genes, and to fully elucidate genotype-phenotype correlations.


Assuntos
Genes Recessivos , Variação Genética , Miopatias da Nemalina/genética , Miopatias da Nemalina/fisiopatologia , Criança , Pré-Escolar , Mapeamento Cromossômico , Cromossomos Humanos Par 2/genética , Ligação Genética , Humanos , Lactente , Escore Lod , Proteínas Musculares/genética , Linhagem
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