Identification of a common molecular basis for combined 17 alpha-hydroxylase/17,20-lyase deficiency in two Mennonite families

Hum Genet. 1989 Jun;82(3):285-6. doi: 10.1007/BF00291172.


During the course of studies to characterize mutations of the CYP17 gene that cause the 17 alpha-hydroxylase-deficient form of congenital adrenal hyperplasia we have discovered two ostensibly unrelated Mennonite families in which affected individuals are homozygous for the same mutation. The defect is a four-base duplication in exon 8 of the CYP17 gene, which alters the reading frame encoding the C-terminal 26 amino acids of cytochrome P450(17 alpha).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenal Hyperplasia, Congenital* / enzymology
  • Adrenal Hyperplasia, Congenital* / genetics
  • Aldehyde-Lyases / deficiency*
  • Aldehyde-Lyases / genetics
  • Canada
  • Cytochrome P-450 Enzyme System / genetics
  • Ethnic Groups*
  • Exons
  • Homozygote
  • Humans
  • Mutation
  • Steroid 17-alpha-Hydroxylase / genetics
  • Steroid Hydroxylases / deficiency*


  • Cytochrome P-450 Enzyme System
  • Steroid Hydroxylases
  • Steroid 17-alpha-Hydroxylase
  • Aldehyde-Lyases