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Mutations in steroid 21-hydroxylase (CYP21)
P C White1, M T Tusie-Luna, M I New
1Division of Pediatric Endocrinology, Cornell University Medical College, New York, New York 10021.
Human Mutation
|January 1, 1994
Summary
Congenital adrenal hyperplasia, often due to 21-hydroxylase deficiency, results from mutations in the CYP21 gene. These mutations, frequently caused by gene conversion between CYP21 and its pseudogene, correlate with disease severity.
Area of Science:
- Endocrinology
- Genetics
- Biochemistry
Background:
- Congenital adrenal hyperplasia (CAH) is an inherited disorder affecting cortisol synthesis.
- Over 90% of CAH cases stem from 21-hydroxylase deficiency, leading to androgen excess and potential mineralocorticoid deficiency.
Purpose of the Study:
- To explain the genetic basis of 21-hydroxylase deficiency in CAH.
- To elucidate the mechanisms generating disease-causing mutations in the CYP21 gene.
Main Methods:
- Analysis of the CYP21 gene and its pseudogene (CYP21P) in the HLA complex.
- Investigating the role of recombination and gene conversion in mutation formation.
Main Results:
- Mutations in CYP21 are the primary cause of CAH.
- Recombination events between CYP21 and CYP21P generate most mutations, either by deletion or apparent gene conversion.
- The extent of enzymatic impairment from specific mutations correlates with clinical CAH severity.
Conclusions:
- Genetic mutations in CYP21, often arising from complex rearrangements with CYP21P, underlie congenital adrenal hyperplasia.
- Understanding these genetic mechanisms is crucial for correlating genotype with CAH phenotype and severity.