GENE REFERENCE / HGNC:2593

CYP17A1

cytochrome P450 family 17 subfamily A member 1

protein-coding gene10q24.32Gene information

What does this gene do?

The CYP17A1 gene provides instructions for making a member of the cytochrome P450 enzyme family. Like other cytochrome P450 enzymes, CYP17A1 is involved in the formation (synthesis) of steroid hormones. This group of hormones includes sex hormones such as testosterone and estrogen, which are needed for normal sexual development and reproduction; mineralocorticoids, which help regulate the body's salt and water balance; and glucocorticoids, which are involved in maintaining blood sugar (glucose) levels and regulating the body's response to stress.

Steroid hormones are synthesized through a series of chemical reactions. The CYP17A1 enzyme performs two important reactions in this process. The enzyme has 17 alpha(α)-hydroxylase activity, converting pregnenalone to 17-hydroxypregnenolone and progesterone to 17-hydroxyprogesterone. These hormone precursors are further processed to produce glucocorticoids and sex hormones. CYP17A1 also has 17,20-lyase activity, which converts 17-hydroxypregnenolone to dehydroepiandrosterone (DHEA). This reaction is integral to the production of sex hormones.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-10-27. Source review: 2016-02.

ClinGen reviews

We found no matching ClinGen review in the data used here. This does not rule out a link between the gene and a condition.

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 644
Submissions for variants in or overlapping this gene: 952
Submissions explicitly reporting this gene: 920
Alleles reported pathogenic / likely pathogenic: 161
VariationIDs with uncertain significance: 105
VariationIDs with conflicting classifications: 16

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about CYP17A1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 161 alleles in CYP17A1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in CYP17A1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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