Table 1.
Forms of congenital adrenal hyperplasia
| Defective enzyme |
Gene/Chromoso me |
Incidence & Populations |
Clinical features | Biomarkers |
|---|---|---|---|---|
| 21-hydroxylase (P450c21) |
CYP21A2/6p21.3 | Classic 1:16,000 Nonclassic <1:1,000 More frequent in Ashkenazi Jews, Mediterraneans, Hispanics, and Yupik Eskimos. |
Adrenal insufficiency in classic forms. Variable degrees of virilization. |
17OH- progesterone, AD, T |
| 11β-hydroxylase (P450c11β) |
CYP11B1/8q24.3 | 1:100,000 in Caucasians; 1:7,000 in Moroccan Jews |
Hypertension in most patients; hypokalemia; virilization |
DOC, 11- deoxycortisol, AD, T |
| 3β- hydroxysteroid dehydrogenase type 2 |
HSD3B2/1p13.1 | Rare | Volume depletion, hyponatremia, and hyperkalemia. 46,XX: virilization 46,XY: undervirilization |
Pregnenolone, 17OH- pregnenolone, DHEA, DHEAS |
| 17- hydroxylase/17,2 0-lyase (P450c17) |
CYP17A1/10q21- q22 |
1:50,000 worldwide; More common in Brazil and Asia |
Hypertension, hypokalemia, and hypogonadism; 46,XX: primary amenorrhea and absence of secondary sexual characteristics. 46,XY: undervirilization, abdominal testes. |
Progesterone, DOC, corticosterone; LH & FSH |
| Steroidogenic acute regulatory protein (StAR) |
STAR/8p11.2 | Rare More frequent in Japanese, Palestinians, Koreans |
Adrenal insufficiency; enlarged, lipid- laden adrenal glands. Female phenotype of external genitalia in both sexes |
All steroids decreased |
| Cholesterol side- chain cleavage enzyme (P450scc) |
CYP11A1/15q23 –q24 |
Rare | Adrenal insufficiency; adrenal glands may appear absent. |
All steroids decreased |
| P450- oxidoreductase deficiency (POR) |
POR/7q11.2 | Rare More common in Japan and Korea |
Volume depletion, skeletal malformations (Antley-Bixler); maternal virilization. 46,XX: mild-to- moderate virilization. 46,XY: undervirilization |
Highly variable profiles, multiple partial defects. |
CYP11B1, 11β-hydroxylase; HSD3B2, 3β-hydroxysteroid dehydrogenase type 2; POR, P450-oxidoreductase deficiency; DOC, 11-deoxycorticosterone; AD, androstenedione; T, testosterone; DHEA, dehydroepiandrosterone; DHEAS, DHEA sulfate; LH, luteinizing hormone; FSH, follicle-stimulating hormone.