title: Frequent deletion and duplication of the steroid 21-hydroxylase genes.
abstract: Congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency is an HLA-linked disorder resulting from a mutation in the 21-OHase B gene encoding the adrenal cytochrome P450 specific for steroid 21-hydroxylation. To identify polymorphisms associated with 21-OHase deficiency, DNA samples from 22 unrelated patients with this disorder were examined with a human cDNA clone encoding the enzyme. Deletions of the active 21-OHase gene were found in almost one-fourth of classical 21-OHase deficiency alleles. In contrast, mild, "nonclassical" 21-OHase deficiency is associated with a duplicated 21-OHase gene.
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000201:enzymology / Q000235:genetics; D002872:Chromosome Deletion; D003181:Complement C4 / Q000235:genetics; D004247:DNA / Q000235:genetics; D008040:Genetic Linkage; D005819:Genetic Markers; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D009693:Nucleic Acid Hybridization; D011110:Polymorphism, Genetic; D013255:Steroid 21-Hydroxylase / Q000235:genetics*; D013250:Steroid Hydroxylases / Q000235:genetics*
chemical_list: D003181:Complement C4; D005819:Genetic Markers; D006680:HLA Antigens; D004247:DNA; D013250:Steroid Hydroxylases; D013255:Steroid 21-Hydroxylase