ST20

Chr 15

suppressor of tumorigenicity 20

Also known as: HCCS-1

NCBI Gene: 400410 ENSG00000180953 UniProt: Q9HBF5

Enables cysteine-type endopeptidase activator activity. Involved in apoptotic signaling pathway and cellular response to UV-C. [provided by Alliance of Genome Resources, Jul 2025]

Research

Enables cysteine-type endopeptidase activator activity. Involved in apoptotic signaling pathway and cellular response to UV-C. [provided by Alliance of Genome Resources, Jul 2025]

ResearchGenerating clinical summary…

Clinical highlights

Interpreting a novel variant

This gene is strongly intolerant of loss-of-function variation in the population, so LoF variants warrant close attention. No curated mechanism annotation is available — see the mechanism card for the computational prediction and its caveats.Based on population constraint only.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

1.76

LOEUF

GOF

Mechanism· predicted

Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.76LOEUF

pLI 0.375

Z-score 0.85

OE 0.00 (0.00–1.76)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

0.04Z-score

OE missense 0.98 (0.76–1.29)

38 obs / 38.6 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.00 (0.00–1.76)

0≤0.351.4

Missense OE?0.98 (0.76–1.29)

0≤0.61.4

Synonymous OE?1.35

0≤1.21.6

LoF obs/exp: 0 / 0.8Missense obs/exp: 38 / 38.6Syn Z: -1.09

Background carrier burden — how many people carry a rare variant somewhere in ST20?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 1,100

84 rare PASS variants

Rare truncating (LoF)

1 in 7,000

18 rare PASS variants

Rare synonymous (reference)

1 in 900

34 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for ST20. A background rate for each class, not the frequency of any particular variant; thin-coverage exons undercount.

By genetic ancestry · 9 gnomAD groups · rare = under 0.1% in that group

Group	People	Missense	Truncating
European (non-Finnish)	~556k	1 in 1,400	1 in 4,900
South Asian	~43k	1 in 420	1 in 720
Remaining (unassigned)	~30k	1 in 910	≈ 1 in 30,000
European (Finnish)	~27k	1 in 420	1 in 1,100
Admixed American	~22k	1 in 380	1 in 700
African / African American	~21k	1 in 370	1 in 890
East Asian	~20k	1 in 410	1 in 2,300
Ashkenazi Jewish	~13k	1 in 320	none seen
Middle Eastern	~2,884	≈ 1 in 960	none seen

Each group is summed over the variants that are rare in that group. Grey ≈ figures rest on fewer than five expected carriers — too few to distinguish groups. Differences mostly reflect how many people were sampled and how much variation each ancestry carries, not disease risk.