Diagnosis of the Martin-Bell syndrome based on structural and functional alterations in the 5 '-untranslated region of the FMR1 gene

Fragile X or Martin-Bell syndrome (MBS) is the most frequent form of heredi tary mental retardation. The primary molecular defects are CGG repeat expan sion in the first exon and methylation of the CpG island of the FMR1 gene, which suppress production of FMRP. Methods of DNA diagnosis and screening f or MBS elaborated within the recent seven years allow efficient detection o f either defect. However, the methods an rather time- and labor-consuming o r expensive. A new PCR-based method was proposed for the analysis of methyl ation in the FMR1 promoter. Advantages and prospects of using this method i n the examination of various groups of people are discussed.