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CYP21A2

Synonyms
CA21H, CAH1, CPS1, CYP21, CYP21B, P450c21B
External resources
Summary
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and hydroxylates steroids at the 21 position. Its activity is required for the synthesis of steroid hormones including cortisol and aldosterone. Mutations in this gene cause congenital adrenal hyperplasia. A related pseudogene is located near this gene; gene conversion events involving the functional gene and the pseudogene are thought to account for many cases of steroid 21-hydroxylase deficiency. Two transcript variants encoding different isoforms have been found for this gene.

Variant Counts

Variant classification counts, according to ACMG guideline on all identified variants among our tested samples, are listed. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc.) are excluded.

Pathogenic
1,104
Likely pathogenic
382
VUS
9,627
Likely benign
5,315
Benign
53

Patient Phenotypes

Proportions of phenotypes among 1213 patients carrying pathogenic or likely pathogenic variants on CYP21A2 gene are displayed below. The following symptoms were found in patients with a variant in CYP21A2. However, patients may have been diagnosed with a different variant.

Phenotype class
Patients in 3billion (%)
Abnormality of the nervous system
42.3%
Abnormality of the musculoskeletal system
28.3%
Abnormality of the eye
25.8%
Abnormality of the cardiovascular system
24.3%
Abnormality of head or neck
22.6%
Abnormality of the ear
15%
Growth abnormality
13.7%
Abnormality of the integument
11.4%
Abnormality of the genitourinary system
11.2%
Abnormality of limbs
10.7%
Abnormality of metabolism homeostasis
9.8%
Abnormality of the digestive system
8.9%
Abnormality of the immune system
7.8%
Abnormality of blood and blood forming tissues
6.8%
Abnormality of the endocrine system
4.8%
Neoplasm
4%
Abnormality of the respiratory system
3.8%
Abnormality of prenatal development or birth
2.6%
Constitutional symptom
1.6%
Abnormality of the voice
0.8%
Abnormality of the breast
0.5%
Abnormal cellular phenotype
0.3%
Abnormality of the thoracic cavity
0%

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