MICROSATELLITE MARKERS IN THE INDIRECT ANALYSIS OF THE STEROID 21-HYDROXYLASE GENE

Prenatal diagnosis and treatment of congenital adrenal hyperplasia due to steroid 21-hydroxylase (21-OH) deficiency has been proved to be ef fective. Screening for a panel of nine point mutations, deletions, and gene conversions allows the identification of most of the mutations, although 6-12 per cent of chromosomes remain uncharacterized. In the p resent study, microsatellite typing in the HLA region was performed in 23 21-OH deficiency families to determine the usefulness of these mar kers in the indirect identification of disease alleles. Two Genethon m arkers (D6S273 and D6S439) in the HLA complex, class III and II region s in 5' and 3', respectively to the CYP21 gene, were typed together wi th a microsatellite at intron 3 of the TAP1 gene also in 3'. The heter ozygosity of these markers provided informativity in all but one famil y, in which only the father was informative. Direct genotyping of the chromosomes confirmed in each case the correct assignment of the disea se alleles in the sibling. The indirect analysis of the 21-OH gene thr ough D6S273, TAP1, and D6S439 microsatellites provides useful informat ion in the molecular analysis of steroid 21-OH deficiency. (C) 1997 by John Wiley & Sons, Ltd.