Mutation screening in British 21-hydroxylase deficiency families and development of novel microsatellite based approaches to prenatal diagnosis.
21-hydroxylase deficiency is a recessively inherited disorder of steroidogenesis, resulting from mutations in the CYP21 gene. This 3.5 kb gene and a highly related CYP21P pseudogene reside on tandemly duplicated 30 kb segments of DNA in the class III HLA region, and the great majority of pathogenic mutations result from sequence exchanges involving the duplicated units. We now describe a comprehensive survey of CYP21 mutations in the British population, encompassing a screen for 17 different mutations in a total of 284 disease chromosomes. The most common mutations were as follows: large scale deletions/conversions (45% of the affected chromosomes), the intron 2 splice mutation (30.3%), R357W (9.8%), and I172N (7.0%). Mutations were detected in over 92% of the chromosomes examined, suggesting that accurate DNA based diagnosis is possible in most cases using the described strategy. In order to extend highly accurate prenatal diagnosis to all families where samples are available from a previously affected child, we have developed a linkage analysis approach using novel, highly informative microsatellite markers from the class III HLA region.
Department of Human Genetics, University of Newcastle upon Tyne, UK.
M
M
Lako
S
S
Ramsden
R D
RD
Campbell
T
T
Strachan
D000312:Adrenal Hyperplasia, Congenital / Q000235:genetics; D015139:Blotting, Southern; D017931:DNA Primers; D005260:Female; D017353:Gene Deletion; D005838:Genotype; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D017354:Point Mutation; D011296:Prenatal Diagnosis; D013255:Steroid 21-Hydroxylase / Q000235:genetics*; D006113:United Kingdom
D017931:DNA Primers; D006680:HLA Antigens; D013255:Steroid 21-Hydroxylase