RESUMO
The p.Thr124Met mutation in the myelin protein zero (MPZ) causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers´ sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch), the founder effect hypothesis for this allele migration is suggestive. Rev. Biol. Trop. 62 (4): 1285-1293. Epub 2014 December 01.
La mutación p.thr124Met en la proteína mielina cero (MPZ) causa la enfermedad de Charcot-Marie-Tooth tipo 2J, una neuropatía periférica con síntomas adicionales como alteraciones pupilares y sordera. Se ha observado en varias familias alrededor del mundo, originarias de Alemania, Bélgica, Japón, Italia y Norteamérica, entre otras. Aquí reportamos a pacientes centroamericanos provenientes de Costa Rica que acarrean esta mutación. Se realizaron análisis clínico, electrofisiológico y molecular de pacientes y controles, incluyendo secuenciación del gen y de marcadores ligados a éste. Estos pacientes comparten casi por completo el haplotipo con dos pacientes belgas no emparentados. Como resultado del análisis de los haplotipos, basado en diez marcadores (siete SNPs, dos microsatélites y un elemento poli-A intrónico), se sugiere que se ha dado un efecto fundador en la migración de este alelo.
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Doença de Charcot-Marie-Tooth/genética , Perda Auditiva Neurossensorial/genética , Proteína P0 da Mielina/genética , Mutação Puntual/genética , Estudos de Casos e Controles , Costa Rica , Doença de Charcot-Marie-Tooth/etnologia , Efeito Fundador , Haplótipos , Perda Auditiva Neurossensorial/etnologia , LinhagemRESUMO
The p.Thr124Met mutation in the myelin protein zero (MPZ) causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers' sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch), the founder effect hypothesis for this allele migration is suggestive.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Perda Auditiva Neurossensorial/genética , Proteína P0 da Mielina/genética , Mutação Puntual/genética , Adulto , Idoso , Estudos de Casos e Controles , Doença de Charcot-Marie-Tooth/etnologia , Costa Rica , Feminino , Efeito Fundador , Haplótipos , Perda Auditiva Neurossensorial/etnologia , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Adulto JovemRESUMO
Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous disorder. All mendelian patterns of inheritance have been described. We identified a homozygous p.A335V mutation in the MED25 gene in an extended Costa Rican family with autosomal recessively inherited Charcot-Marie-Tooth neuropathy linked to the CMT2B2 locus in chromosome 19q13.3. MED25, also known as ARC92 and ACID1, is a subunit of the human activator-recruited cofactor (ARC), a family of large transcriptional coactivator complexes related to the yeast Mediator. MED25 was identified by virtue of functional association with the activator domains of multiple cellular and viral transcriptional activators. Its exact physiological function in transcriptional regulation remains obscure. The CMT2B2-associated missense amino acid substitution p.A335V is located in a proline-rich region with high affinity for SH3 domains of the Abelson type. The mutation causes a decrease in binding specificity leading to the recognition of a broader range of SH3 domain proteins. Furthermore, Med25 is coordinately expressed with Pmp22 gene dosage and expression in transgenic mice and rats. These results suggest a potential role of this protein in the molecular etiology of CMT2B2 and suggest a potential, more general role of MED25 in gene dosage sensitive peripheral neuropathy pathogenesis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Substituição de Aminoácidos , Proteínas de Ciclo Celular , Doença de Charcot-Marie-Tooth/genética , Complexo Mediador , Proteínas da Mielina , Proteínas Nucleares , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adulto , Sequência de Aminoácidos , Animais , Animais Geneticamente Modificados , Sequência de Bases , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Doença de Charcot-Marie-Tooth/fisiopatologia , Costa Rica , Análise Mutacional de DNA , Modelos Animais de Doenças , Feminino , Dosagem de Genes , Genótipo , Humanos , Masculino , Complexo Mediador/química , Complexo Mediador/genética , Complexo Mediador/metabolismo , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Proteínas da Mielina/genética , Proteínas da Mielina/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Linhagem , Conformação Proteica , RatosRESUMO
OBJECTIVE: To describe the clinical, electrophysiologic and morphologic features of a Costa Rican family with an autosomal dominant inherited Charcot-Marie-Tooth (CMT) neuropathy. METHODS: The field study took place in Costa Rica, Central America. Seven patients underwent neurological examinations and standard electrodiagnostic tests, and a sural nerve biopsy was taken from one patient. Fifteen family members were screened for gene defects associated with CMT disease. RESULTS: Characteristic features of this family were a late age of onset (35-56 years), positive sensory symptoms and muscle cramps. Based on electrodiagnostic and morphologic data, the patients were classified as having a CMT2 neuropathy. The CMT1A duplication/HNPP deletion and point mutations in genes PMP22, MPZ, Cx32 and EGR2 implicated in the most common types of CMT disease were excluded. Subsequently, almost all known CMT loci were excluded by linkage analysis. DISCUSSION: Features of this family were a late age of onset and positive sensory symptoms. This new autosomal dominant CMT neuropathy is associated with an unknown gene defect.
Assuntos
Doença de Charcot-Marie-Tooth/diagnóstico , Doença de Charcot-Marie-Tooth/genética , Saúde da Família , Adulto , Idade de Início , Idoso , Doença de Charcot-Marie-Tooth/patologia , Doença de Charcot-Marie-Tooth/fisiopatologia , Costa Rica , Feminino , Genes Dominantes , Humanos , Masculino , Pessoa de Meia-Idade , LinhagemRESUMO
Glaucoma is the second most frequent cause of irreversible blindness worldwide. Genetic factors have been implicated in the development of the disease. So far six loci (GLC1A-GLC1F) and two genes (TIGR/MYOC and OPTN) are involved in the development of juvenile (JOAG) and adult onset or chronic primary open angle glaucoma (COAG), while two loci (GLC3A,GLC3B) and one gene (CYP1B1) are known for primary congenital glaucoma (PCG). Here we summarize the results of the first genetic studies of glaucoma in Costa Rica. Nine families: 1 with JOAG, 1 with PCG and 7 with COAG were screened for mutations at the known genes. A 10 bp duplication, 1546-1555dupTCATGCCACC, at the CYP1B1 gene, causes, in homozygous state, glaucoma in the consanguineous PCG family. This mutation has been found in different countries and generates an early stop codon that termitates protein synthesis 140 amino acids earlier than the normal allele. In exon 1 of the T1GR/MYOC the innocuous Arg76Lys variant was found in two of the COAG families. In the OPTN gene two variants in the coding region (Thr34Thr, Met 98Lys) and 7 intronic changes were found in other Costa Rican glaucoma patients. One of the COAG families was chosen for a genome scan with 379 microsatellite markers and linkage analysis. LOD scores [quot ]suggestive[quot ] of linkage were obtained for several chromosomal regions. Evidence indicates that hereditary glaucoma in Costa Rica is highly heterogeneous and that further studies in the country will probably disclose some up to now unknown genes responsible for the disease.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Proteínas do Citoesqueleto , Ligação Genética , Glaucoma/genética , Glicoproteínas/genética , Hidrocarboneto de Aril Hidroxilases/genética , Mutação/genética , Proteínas do Olho/genética , Costa Rica , LinhagemRESUMO
Charcot-Marie-Tooth disease (CMT) comprises a heterogeneous group of hereditary motor and sensory peripheral neuropathies. The autosomal recessive axonal form of CMT (ARCMT2) is rare. Eight patients of a large consanguineous family of Spanish ancestry in Costa Rica were diagnosed with ARCMT2B; previous genetic studies of this family revealed linkage to chromosome 19q13.3. The clinical and electrophysiological features of these patients are reported. All patients presented with a symmetric motor and sensory neuropathy, which was more pronounced in the lower limbs. Further, distal muscle wasting and impaired deep tendon reflexes were found. Age at onset was between 26 and 42 years, and the disease duration ranged from 2 to 19 years. Electrophysiological studies revealed a primary axonal degenerative process. The clinical characteristics of this family differed in several aspects from previously reported families with ARCMT2.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Cromossomos Humanos Par 19 , Nervos Periféricos/fisiopatologia , Potenciais de Ação/fisiologia , Adulto , Idade de Início , Atrofia/fisiopatologia , Doença de Charcot-Marie-Tooth/fisiopatologia , Mapeamento Cromossômico , Costa Rica/etnologia , Eletromiografia/métodos , Eletrofisiologia/métodos , Saúde da Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Condução Nervosa/fisiologia , Linhagem , Tempo de Reação/fisiologia , Reflexo de Estiramento/fisiologiaRESUMO
Glaucoma is the second most frequent cause of irreversible blindness worldwide. Genetic factors have been implicated in the development of the disease. So far six loci (GLC1A-GLC1F) and two genes (TIGR/MYOC and OPTN) are involved in the development of juvenile (JOAG) and adult onset or chronic primary open angle glaucoma (COAG), while two loci (GLC3A,GLC3B) and one gene (CYP1B1) are known for primary congenital glaucoma (PCG). Here we summarize the results of the first genetic studies of glaucoma in Costa Rica. Nine families: 1 with JOAG, 1 with PCG and 7 with COAG were screened for mutations at the known genes. A 10 bp duplication, 1546-1555dupTCATGCCACC, at the CYP1B1 gene, causes, in homozygous state, glaucoma in the consanguineous PCG family. This mutation has been found in different countries and generates an early stop codon that termitates protein synthesis 140 amino acids earlier than the normal allele. In exon 1 of the T1GR/MYOC the innocuous Arg76Lys variant was found in two of the COAG families. In the OPTN gene two variants in the coding region (Thr34Thr, Met 98Lys) and 7 intronic changes were found in other Costa Rican glaucoma patients. One of the COAG families was chosen for a genome scan with 379 microsatellite markers and linkage analysis. LOD scores "suggestive" of linkage were obtained for several chromosomal regions. Evidence indicates that hereditary glaucoma in Costa Rica is highly heterogeneous and that further studies in the country will probably disclose some up to now unknown genes responsible for the disease.
Assuntos
Hidrocarboneto de Aril Hidroxilases/genética , Proteínas do Citoesqueleto/genética , Proteínas do Olho/genética , Ligação Genética/genética , Glaucoma/genética , Glicoproteínas/genética , Mutação/genética , Adulto , Idoso , Costa Rica , Citocromo P-450 CYP1B1 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , LinhagemRESUMO
Charcot-Marie-Tooth disease type 1B (CMT 1B) is caused by mutations in the gene coding for peripheral myelin protein zero (MPZ, P0) that plays a fundamental role in adhesion and compaction of peripheral myelin. Here we report a Costa Rican family with a hereditary peripheral neuropathy due to a novel Tyr145Ser MPZ mutation. Four family members were heterozygously affected; two siblings of two heterozygous carriers were homozygous for this mutation. On neurological examination the heterozygous parents and their homozygous children both showed distal sensory deficits. The mother and the siblings displayed impaired deep tendon reflexes and mild sensory ataxia. The homozygous individuals were more severely affected with an earlier age of onset, distal motor weakness, and pupillary abnormalities. Electrophysiological studies revealed both signs of demyelination and axonal nerve degeneration. The sural nerve biopsy of one sibling showed thinly myelinated nerve fibers, onion bulb formation, and clusters of regenerating fibers. On electron microscopy axonal degeneration and decompaction of inner myelin layers were found. This Costa Rican family shows phenotypic variability depending on the homozygous or heterozygous state of the Tyr145Ser mutation carriers.
Assuntos
Doença de Charcot-Marie-Tooth/genética , Proteína P0 da Mielina/genética , Mutação Puntual , Doença de Charcot-Marie-Tooth/patologia , Costa Rica , Análise Mutacional de DNA , Saúde da Família , Feminino , Heterozigoto , Homozigoto , Humanos , Masculino , Linhagem , Fenótipo , Nervo Sural/patologiaRESUMO
PURPOSE: To present new molecular genetic data on primary congenital glaucoma from 2 families, 1 isolated case and 3 familial cases due to mutations in the cytochrome P-450 1B1 (CYP1B1) gene. METHODS: All diagnoses were made by slit-lamp biomicroscopy, gonioscopy, cornea and optic disk measurements, ultrasound-biometry, and automated static threshold perimetry where possible. Mutation screening was performed by direct sequence analysis of DNA extracted from peripheral blood of the patients and their relatives. RESULTS: For the isolated case, a child of 4 years, a homozygous nucleotide deletion within a tetrad of cytosines (nt622-625, 622delC) was found leading to a predicted nonsense codon 93 truncating the protein by 450 amino acids. For the familial cases, the 3 affected members showed a homozygous mutation 1,546-1,555dupTCATGCCACC for which 9 healthy relatives proved to be heterozygous. The phenotypic expression of these 3 patients varied widely. CONCLUSION: Our results confirm the crucial role of CYP1B1 mutations for congenital glaucoma.