title: Missense mutation serine106----proline causes 17 alpha-hydroxylase deficiency.
abstract: Steroid 17 alpha-hydroxylase deficiency is caused by defects in cytochrome P450c17, the single enzyme that has 17-alpha hydroxylase and 17,20-lyase activities. We describe a rapid and efficient polymerase chain reaction tactic for identifying these genetic lesions and identify Ser106----Pro as the cause of 17 alpha-hydroxylase deficiency in two unrelated homozygous patients from Guam. We used site-directed mutagenesis of the normal P450c17 cDNA to construct the Pro106 mutant, and expressed both the normal and mutant sequences in monkey COS-1 cells and in yeast. Expression of the normal sequence permitted the cells to convert pregnenolone to 17-OH pregnenolone, progesterone to 17-OH progesterone, and 17-OH pregnenolone to dehydroepiandrosterone, showing the normal sequence conferred both 17 alpha-hydroxylase and 17,20-lyase activities. Expression of the mutant sequence generated P450c17 mRNA, but conferred none of these activities, proving that the Ser106----Pro mutation abolished the 17 alpha-hydroxylase and 17,20-lyase activities. An HhaI restriction site created by the mutation should permit screening of large populations.
authors.affiliation: Department of Pediatrics, University of California, San Francisco 94143.
authors.forename: D
authors.initials: D
authors.lastname: Lin
authors.forename: J A
authors.initials: JA
authors.lastname: Harikrishna
authors.forename: C C
authors.initials: CC
authors.lastname: Moore
authors.forename: K L
authors.initials: KL
authors.lastname: Jones
authors.forename: W L
authors.initials: WL
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000312:Adrenal Hyperplasia, Congenital; D000483:Alleles; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002855:Chromatography, Thin Layer; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006720:Homozygote; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D016133:Polymerase Chain Reaction; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D011392:Proline / Q000737:chemistry*; D012313:RNA / Q000235:genetics; D012694:Serine / Q000737:chemistry*; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics
chemical_list: D012694:Serine; D011374:Progesterone; D012313:RNA; D011284:Pregnenolone; D004247:DNA; D011392:Proline; D013254:Steroid 17-alpha-Hydroxylase