CYP20A1

Chr 2

cytochrome P450 family 20 subfamily A member 1

Also known as: CYP-M

NCBI Gene: 57404 ENSG00000119004 UniProt: Q6UW02

The protein is a member of the cytochrome P450 superfamily but lacks key conserved motifs including part of the heme binding site and the I-helix motif, suggesting it may have atypical enzymatic properties compared to other P450 enzymes. This gene is extremely intolerant to loss-of-function variants (pLI ~1.0), indicating it is under strong selective pressure and likely essential for normal function. However, no definitive human disease associations have been established for CYP20A1 mutations despite its apparent functional importance.

ResearchSummary from RefSeq

This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein lacks one amino acid of the conserved heme binding site. It also lacks the conserved I-helix motif AGX(D,E)T, suggesting that its substrate may carry its own oxygen. [provided by RefSeq, Jul 2008]

ResearchGenerating clinical summary…

LOEUF 1.37

Clinical Summary— CYP20A1

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

53 VUS of 82 total submissions

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.37LOEUF

pLI 0.000

Z-score 0.10

OE 0.98 (0.71–1.37)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

0.37Z-score

OE missense 0.93 (0.83–1.04)

215 obs / 231.0 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.98 (0.71–1.37)

0≤0.351.4

Missense OE?0.93 (0.83–1.04)

0≤0.61.4

Synonymous OE?0.97

0≤1.21.6

LoF obs/exp: 25 / 25.6Missense obs/exp: 215 / 231.0Syn Z: 0.23

ClinVar Variant Classifications

82 submitted variants in ClinVar

ClinVar

Classification Summary

VUS53

Likely Benign2

Benign2

VUS

Likely Benign

Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

Classification	Missense + Inframe	Total
Pathogenic	0	0
Likely Pathogenic	0	0
VUS	53	53
Likely Benign	2	2
Benign	2	2
Total	57	57

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

29 pathogenic / likely-pathogenic (of 31) ClinVar copy-number / structural variants overlap CYP20A1 — these span large chromosomal regions, not the gene specifically, and are excluded from the counts above. Explore in CNV tools →