[Adrenogenital syndrome. II. Molecular biology]

The adrenogenital syndrome (AGS) is usually caused by steroid 21-hydroxylase deficiency. Two steroid 21-hydroxylase genes are present within the major histocompatibility complex (MHC) on chromosome 6: an active gene (CYP21) and a pseudogene (CYP21P). Several types of mutations have been described; these mutations can be categorized as gene deletions, gene duplications, gene conversions and smaller mutations inside the gene. Some of these cause a defect in the CYP21 gene, possibly resulting in 21-hydroxylase deficiency. Apart from the intrinsic scientific value of these results, the methods applied become increasingly important in diagnostics.