RESUMO
Spinal muscular atrophy (SMA) is an autosomal recessive, neurodegenerative disorder characterised commonly by proximal muscle weakness and wasting in the absence of sensory signs. Deletion or disruption of the SMN1 gene causes the disease. The SMN1 gene is located within an inverted duplication on chromosome 5q13 with the genes SMN2, NAIP and GTF2H2. MLPA analysis of 13 Cypriot SMA patients revealed that, 12 patients carried a homozygous SMN1 gene deletion and one patient carried two copies of the SMN1 gene. Two of 13 cases were a consequence of a paternally originating de novo mutation. Five genotypes were identified within the population, with the most frequent being a homozygous SMN1 and NAIP genes deletion. In conclusion, genotype-phenotype correlation revealed that SMN2 is inversely related to disease severity and that NAIP and GTF2H2 act as negative modifiers. This study provided, for the first time, a comprehensive overview of gene copy numbers and inheritance patterns within Cypriot SMA families.
Assuntos
Atrofias Musculares Espinais da Infância/genética , Chipre , Análise Mutacional de DNA , Família , Feminino , Dosagem de Genes , Estudos de Associação Genética , Humanos , Padrões de Herança , Masculino , Repetições de Microssatélites , Mutação , Linhagem , Proteína 1 de Sobrevivência do Neurônio Motor/genéticaRESUMO
A cluster of Friedreich's ataxia patients has been previously investigated in two neighbouring villages of the Paphos district of Cyprus. Molecular genetic studies revealed that all patients had the most common mutation, a homozygous expansion of the GAA triplet repeat in the first intron of the frataxin gene. The present study is aimed at estimating the mutation carrier frequency in the broader area of Paphos. Overall, 1050 individuals originating from the Paphos district took part in the programme. Blood samples were collected for a period of 18 months, on a voluntary basis, after signing a consent form, and analysis of the GAA triplet repeat was performed. The frequency of mutation carriers in the broader area of the Paphos district, and excluding the two neighbouring cluster villages, is estimated to be high. We recommend that an organized prevention programme be implemented to cover the population from this region.
