Congenital adrenal hyperplasia because of 21-hydroxylase deficiency. A genetic disorder of interest to obstetricians and gynecologists.
Level 5 - mechanism / opinion, no new human data
Narrative review without systematic search or meta-analysis.
PubMed 19228439 · doi:10.1097/OGX.0b013e318193301b
What was done
This is a narrative review detailing the clinical, epidemiological, and genetic aspects of congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency, aimed at obstetricians and gynecologists. The abstract reports general disease frequencies, phenotypic presentations of classical and nonclassical variants, and molecular genetics involving the CYP21A2 gene and CYP21A1P pseudogene on chromosome 6p21.3.
What was found
Classical CAH occurs in 1:5,000 to 1:15,000 live neonates in North America and Europe. Nonclassical CAH (NC-CAH) occurs in approximately 0.2% of the general white population. The CYP21A2 gene shares approximately 98% sequence homology with the pseudogene CYP21A1P. Inactivating mutations driving the disease include complete gene deletions, large gene conversions, and pseudogene-derived mutations. Clinically, classical cases present with salt-wasting and external genital virilization, while NC-CAH presents with hyperandrogenic signs such as menstrual irregularity, hirsutism, short stature, obesity, and subfertility, overlapping significantly with polycystic ovary syndrome.
Why it matters
It provides obstetricians and gynecologists with an overview of how nonclassical 21-hydroxylase deficiency mimics polycystic ovary syndrome and highlights the genetic basis for carrier and diagnostic testing.
Limits
This is a narrative review presenting established background knowledge rather than primary data or systematic syntheses. Specific literature search dates, inclusion criteria, and formal risk of bias assessments are not reported in the abstract.
Cited by
- supports Carrying two copies of a genetic mutation causing adrenal androgen overproduction (such as non-classical congenital adrenal hyperplasia) can cause infertility, whereas heterozygosity (carrying one copy) causes androgen overproduction without causing infertility.