PRENATAL-DIAGNOSIS OF FRIEDREICH ATAXIA - IMPROVED ACCURACY BY USING NEW GENETIC FLANKING MARKERS

Friedreich ataxia is a neurodegerative disorder with autosomal recessi ve inheritance. Since the gene causing mutation has not yet been ident ified, prenatal, predictive, and carrier diagnoses are based on indire ct haplotype analysis with closely linked markers. Until recently, onl y distal markers were available and their physical distance to the Fri edreich ataxia (FRDA) gene remained elusive. The identification of clo se flanking markers that mark out the boundaries of the FRDA locus and reduce the critical genomic region which contains the gene allows for the first time misdiagnosis due to undetectable recombination to be a voided and diagnosis accuracy to be greatly improved. In this sense, w e have verified a prenatal diagnosis in which the fetus was diagnosed as an unaffected carrier last year with a confidence of 95 per cent. B y using the new flanking markers, the diagnosis improved and confidenc e reached almost 100 per cent.