title: Heterogeneity in the gene locus for steroid 21-hydroxylase deficiency.
abstract: DNA was analysed from 33 patients with congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency. In each case Southern blots were prepared from a number of restriction enzyme digests and hybridised with probes for both the 21-hydroxylase and the adjacent fourth component of complement (C4). Evidence for deletion of the active 21-hydroxylase gene (CYP21B) was found in 13 cases and in 10 of these the deletion included the adjacent C4B gene, leading to a hybrid CYP21A/CYP21B gene. Deletion of CYP21B alone was found in one patient, the remaining two cases appearing to have the active gene replaced by the inactive pseudogene. Duplications of the CYP21A-C4B region and deletion of the pseudogene are also described. In a further 12 cases no gross abnormality could be found.
authors.affiliation: Department of Clinical Biochemistry, Institute of Child Health, London.
authors.forename: G
authors.initials: G
authors.lastname: Rumsby
authors.forename: A H
authors.initials: AH
authors.lastname: Fielder
authors.forename: W M
authors.initials: WM
authors.lastname: Hague
authors.forename: J W
authors.initials: JW
authors.lastname: Honour
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000201:enzymology / Q000235:genetics*; D015139:Blotting, Southern; D002872:Chromosome Deletion; D002896:Chromosomes, Human, Pair 6; D003181:Complement C4 / Q000235:genetics; D015342:DNA Probes; D006801:Humans; D013255:Steroid 21-Hydroxylase / Q000235:genetics*; D013250:Steroid Hydroxylases / Q000235:genetics*
chemical_list: D003181:Complement C4; D015342:DNA Probes; D013250:Steroid Hydroxylases; D013255:Steroid 21-Hydroxylase