RESUMO
BACKGROUND: Mutations in the leucine-rich-repeat kinase 2 (LRRK2) gene have been identified in families with autosomal dominant Parkinson's disease (ADPD), the most common of which is the p.G2019S substitution that has been found at varying frequencies worldwide. Because of the size of the LRRK2 gene, few studies have analysed the entire gene in large series of ADPD families. METHODS: We performed extensive mutation analyses of all 51 coding exons of the LRRK2 gene in index cases from 226 Parkinson's disease families compatible with autosomal dominant inheritance, mostly from France (n = 182) and North Africa (n = 14). RESULTS: We found 79 sequence variants, 29 of which were novel. Eight potentially or proven pathogenic mutations were found in 22 probands (9.7%). There were four novel amino acid substitutions that are potentially pathogenic (p.S52F, p.N363S, p.I810V, p.R1325Q) and two novel variants, p.H1216R and p.T1410M, that are probably not causative. The common p.G2019S mutation was identified in 13 probands (5.8%) including six from North Africa (43%). The known heterozygous p.R1441H and p.I1371V mutations were found in two probands each, and the p.E334K variant was identified in one single patient. Most potentially or proven pathogenic mutations were located in the functional domains of the Lrrk2 protein. CONCLUSION: This study leads us to conclude that LRRK2 mutations are a common cause of autosomal dominant Parkinson's disease in Europe and North Africa.
Assuntos
Transtornos Parkinsonianos/genética , Proteínas Serina-Treonina Quinases/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , População Negra/genética , Distribuição de Qui-Quadrado , Análise Mutacional de DNA/métodos , Feminino , Frequência do Gene , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina , Masculino , Pessoa de Meia-Idade , Mutação , Transtornos Parkinsonianos/diagnóstico , Linhagem , População Branca/genéticaRESUMO
BACKGROUND: Dystonia syndromes constitute a heterogeneous group of phenotypes that may be caused by different heredodegenerative, metabolic, or genetic diseases. OBJECTIVE: To describe the characteristics of an unusual dystonia-plus phenotype associated with cerebellar atrophy. METHODS: We selected patients with predominant dystonia and cerebellar atrophy among the 861 families referred to us for genetic testing from 1992 to 2003. The main secondary heredodegenerative causes and the major genes responsible for hereditary dystonias and autosomal dominant or recessive ataxias were excluded. RESULTS: We identified 12 patients in 8 families with an unusual dystonia-plus phenotype characterized by dystonia and cerebellar atrophy on brain MRI. The mean age at onset was 27.3 +/- 11.5 years (range: 9 to 42 years) and the mean disease duration 14.7 +/- 7.7 years (range: 4 to 30). At onset, dystonia was focal or multifocal, mainly affecting vocal cords (n = 8) and upper limbs (n = 2). During the disease course spasmodic dysphonia became severe in five patients, leading to complete aphonia in two. Dystonia became generalized in five. Cerebellar ataxia was limited to unsteadiness in most patients and progressed very slowly. The paucity of clinical cerebellar signs contrasted with the marked cerebellar atrophy on brain MRI in most patients. Four families with two affected sibs support the hypothesis of an autosomal recessive disorder. However, X-linked inheritance is possible since only men were affected. CONCLUSION: We have characterized an unusual familial phenotype associating dystonia and cerebellar atrophy in 12 male patients.
Assuntos
Doenças Cerebelares/patologia , Doenças Cerebelares/fisiopatologia , Cerebelo/patologia , Cerebelo/fisiopatologia , Distúrbios Distônicos/patologia , Distúrbios Distônicos/fisiopatologia , Adulto , Atrofia/genética , Atrofia/patologia , Atrofia/fisiopatologia , Ataxia Cerebelar/genética , Ataxia Cerebelar/patologia , Ataxia Cerebelar/fisiopatologia , Doenças Cerebelares/genética , Transtornos Cromossômicos/genética , Análise Mutacional de DNA , Progressão da Doença , Distúrbios Distônicos/genética , Genes Recessivos/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Predisposição Genética para Doença/genética , Testes Genéticos , Genótipo , Humanos , Padrões de Herança/genética , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação/genética , FenótipoRESUMO
In order to determine the frequency and the characteristics of neuropathies in chronic respiratory insufficiency, a systematic study of 43 patients affected by a chronic obstructive pulmonary disease was performed. In addition to neurological and electrophysiological examinations (including 6 nerve conduction studies on median, ulnar and peroneal nerves and EMG of 4 to 8 muscles), nerve and muscle biopsies (of the superficial peroneal nerve and lateral peroneus brevis muscle) were performed in 13 cases. Polyneuropathies were found in 74% patients: but mild in 39%, severe in 35%. Most were subclinical or poorly symptomatic. We determined the importance and distribution of abnormalities on the different nerves. From this we established that neuropathies are mixed but predominantly of the axonal type. Axonal degeneration and demyelination were confirmed by nerve biopsy; muscles presented neurogenic atrophy. Statistical analysis showed that the duration of hypoxemia was related to neuropathy. The pathogeny of these neuropathies is discussed.