Haplotypes of the steroid 21-hydroxylase gene region encoding mild steroid 21-hydroxylase deficiency

Barbro Haglund-Stengler, E. Martin Ritzén, Jan Gustafsson, Holger Luthman

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38 Scopus citations


Haplotypes of the complement 4 (C4) and steroid 21-hydroxylase [21-OHase; steroid hydrogen-donor: oxygen oxidoreductase (21-hydroxylating), EC] repeated gene complex were studied in nine families with at least one member affected with a mild form of 21-OHase deficiency. DNA probes from different parts of the repeated C4/21-OHase unit were used to follow the segregation of hybridization patterns in the families. Ten structurally distinct haplotypes of the C4/21-OHase gene region were identified, and the encoded phenotype was assigned to 34 of the 36 C4/21-OHase haplotypes. Four structurally different haplotypes with three C4/21-OHase repeat units were found. Eight of the nine haplotypes found with triplications of the C4/21-OHase repeat unit encoded the mild form of 21-OHase deficiency, whereas one particular triplicated haplotype encoded a severe form of the disease. In one case the mild form of 21-OHase deficiency was encoded by a haplotype with a single C4/21-OHase repeat unit. Mild 21-OHase deficiency was predicted in a patient by the presence of a triplicated haplotype. The finding of deranged 21-OHase genes on all triplicated C4/21-OHase haplotypes indicate that most of these common haplotypes carry mutated 21-OHase genes, and thus may cause functional polymorphism of general importance in the population.

Original languageEnglish
Pages (from-to)8352-8356
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number19
StatePublished - Oct 1 1991


  • Congenital adrenal hyperplasia
  • Triplicated genes

ASJC Scopus subject areas

  • General
  • Genetics

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