Deficiency of steroid 17-alpha-monooxygenase: genes and variants
Deficiency of steroid 17-alpha-monooxygenase is linked to 1 analyzed protein (CYP17A1). 40 DNA variants are known to cause it; 21 more are uncertain, and 1 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Deficiency of steroid 17-alpha-monooxygenase
CYP17A1: Steroid 17-alpha-hydroxylase/17,20 lyase
Its 17-alpha-hydroxylase and 17,20-lyase activities direct adrenal and gonadal steroid synthesis toward glucocorticoids and sex steroids. Biallelic deficiency causes 17-alpha-hydroxylase/17,20-lyase deficiency with hypertension, hypokalemia, and impaired sexual development.
40 disease-causing and 21 uncertain variants in CYP17A1 are linked to Deficiency of steroid 17-alpha-monooxygenase.
Known disease-causing variants in Deficiency of steroid 17-alpha-monooxygenase
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| CYP17A1 H373D | 373 | Disease-causing (★★) | |
| CYP17A1 H373Y | 373 | Disease-causing (★★) | |
| CYP17A1 H373N | 373 | Disease-causing (★★) | |
| CYP17A1 H373L | 373 | Disease-causing (★★) | |
| CYP17A1 P409L | 409 | Disease-causing (★★) | |
| CYP17A1 R416C | 416 | Disease-causing (★★) | |
| CYP17A1 R440H | 440 | Disease-causing (★★) | |
| CYP17A1 P409R | 409 | Disease-causing (★★) | |
| CYP17A1 R416H | 416 | Disease-causing (★★) | |
| CYP17A1 R440C | 440 | Disease-causing (★★) | |
| CYP17A1 M1T | 1 | Disease-causing (★★) | |
| CYP17A1 M1I | 1 | Disease-causing (★★) | |
| CYP17A1 M1V | 1 | Disease-causing (★★) | |
| CYP17A1 R496C | 496 | Disease-causing (★★) | |
| CYP17A1 R496H | 496 | Disease-causing (★★) | |
| CYP17A1 R347C | 347 | Disease-causing (★★) | |
| CYP17A1 R362H | 362 | Disease-causing (★★) | |
| CYP17A1 W406R | 406 | Disease-causing (★★) | |
| CYP17A1 G436R | 436 | Disease-causing (★★) | |
| CYP17A1 R449C | 449 | Disease-causing (★★) | |
| CYP17A1 A82D | 82 | Disease-causing (★★) | |
| CYP17A1 R347H | 347 | Disease-causing (★★) | |
| CYP17A1 F435S | 435 | Disease-causing (★★) | |
| CYP17A1 R449H | 449 | Disease-causing (★★) | |
| CYP17A1 R96Q | 96 | Disease-causing (★★) | |
| CYP17A1 S106P | 106 | Disease-causing (★★) | |
| CYP17A1 R125Q | 125 | Disease-causing (★★) | |
| CYP17A1 P342T | 342 | Disease-causing (★★) | |
| CYP17A1 A174E | 174 | Disease-causing (★★) | |
| CYP17A1 I332T | 332 | Disease-causing (★★) | |
| CYP17A1 A398V | 398 | Disease-causing (★★) | |
| CYP17A1 P428L | 428 | Disease-causing (★★) | |
| CYP17A1 R239Q | 239 | Disease-causing (★★) | |
| CYP17A1 I296T | 296 | Disease-causing (★★) | |
| CYP17A1 R358Q | 358 | Disease-causing (★★) | |
| CYP17A1 P414L | 414 | Disease-causing (★) | |
| CYP17A1 L433S | 433 | Disease-causing (★) | |
| CYP17A1 C442R | 442 | Disease-causing (★) | |
| CYP17A1 P434L | 434 | Disease-causing (★) | |
| CYP17A1 N177D | 177 | Disease-causing (★) |
Uncertain variants in Deficiency of steroid 17-alpha-monooxygenase that look disease-causing
| Variant | Position | Protein part | Clinical label | Evidence |
|---|---|---|---|---|
| CYP17A1 W406G | 406 | Uncertain (★) | +6: 3 other pathogenic changes within 3 positions; W406R at the same position is pathogenic; not seen in the gnomAD population database; AlphaMissense 0.96 |
Which prediction tools work for Deficiency of steroid 17-alpha-monooxygenase
How often each tool ranks a disease-causing variant above a harmless one (AUROC × 100).
- PolyPhen-2: 100 out of 100 (learned from overlapping clinical labels, so this is optimistic)
- SIFT: 100 out of 100
Same protein, different disease
- Congenital adrenal hyperplasia is also caused by CYP17A1 variants; they fall in the same places as the Deficiency of steroid 17-alpha-monooxygenase variants (13 disease-causing).
- 17-alpha-hydroxylase/17,20-lyase deficiency, combined complete is also caused by CYP17A1 variants; they fall partly in the same places as the Deficiency of steroid 17-alpha-monooxygenase variants (3 disease-causing).
Diseases related to Deficiency of steroid 17-alpha-monooxygenase
- Congenital adrenal hyperplasia, also linked to CYP17A1
- Differences in sex development, also linked to CYP17A1
- Prostate cancer, also linked to CYP17A1
- 17-alpha-hydroxylase/17,20-lyase deficiency, combined complete, also linked to CYP17A1
- 17-alpha-hydroxylase/17,20-lyase deficiency, combined partial, also linked to CYP17A1
Frequently asked questions
Which genes are linked to Deficiency of steroid 17-alpha-monooxygenase?
In CATVariant, Deficiency of steroid 17-alpha-monooxygenase is linked to 1 analyzed protein: CYP17A1 (Steroid 17-alpha-hydroxylase/17,20 lyase).
How many genetic variants are linked to Deficiency of steroid 17-alpha-monooxygenase?
62 variants: 40 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 21 are of uncertain significance or have conflicting reports.
Which uncertain variants in Deficiency of steroid 17-alpha-monooxygenase look disease-causing?
1 uncertain variants reach the likely-pathogenic range of the ACMG/AMP points scale on computable evidence, for example CYP17A1 W406G. These are leads for expert review, not diagnoses.
Which variant effect predictor works best for Deficiency of steroid 17-alpha-monooxygenase?
Among tools not trained on clinical labels, SIFT separates this disease's known disease-causing variants from harmless ones best (AUROC 1.00, based on 37 disease-causing and 8 harmless variants).
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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