Fragile X founder effect and distribution of CGG repeats among the mentally retarded population of Andalusia, South Spain

AUTOR(ES)

Diego, Yolanda de, Hmadcha, Abdelkrim, Moron, Francisco, Lucas, Miguel, Carrasco, Mercedes, Pintado, Elizabeth

FONTE

Genetics and Molecular Biology

DATA DE PUBLICAÇÃO

2002

RESUMO

Fragile X syndrome is the most common inherited form of mental retardation. We investigated the prevalence of the Fragile X syndrome in the population with mental retardation of unknown etiology in Andalusia, South Spain. We analyzed 322 unrelated patients (280 males and 42 females), and found a fragile X syndrome frequency of 6.5%. Among the non-fragile X chromosomes, the 29 CGG repeat was the most common allele. At the linked microsatellite DXS548 locus, we found a new allele which we called "allele 10" (17 CA). Similar to other south European populations, allele 2 (25 CA) at the DXS548 locus and the fragile X allele were in linkage disequilibrium supporting the idea of a common founder chromosome predisposing to the CGG expansion.

Documentos Relacionados

• Clinical checklists in the selection of mentally retarded males for molecular screening of fragile X syndrome
• The fragile X syndrome d(CGG)n nucleotide repeats form a stable tetrahelical structure.
• Methylation mosaicism of 5′-(CGG)n-3′ repeats in fragile X, premutation and normal individuals
• Unusual mutations in high functioning fragile X males: apparent instability of expanded unmethylated CGG repeats.
• Direct analysis of the FMR-1 gene provides an explanation for an exceptional case of a fragile X negative, mentally retarded male in a fragile X family.