PROS1

Chr 3ADAR

protein S

Also known as: PROS, PS21, PS22, PS23, PS24, PS25, PSA, THPH5

Protein S is a vitamin K-dependent anticoagulant plasma protein that serves as a cofactor for activated protein C in degrading coagulation factors Va and VIIIa to prevent excessive blood clotting. Mutations cause thrombophilia 5 due to protein S deficiency, which can be inherited in either autosomal dominant or autosomal recessive patterns. This gene is not highly constrained against loss-of-function variants, reflecting the fact that partial protein S deficiency is compatible with life but increases thrombotic risk.

GeneReviewsOMIMResearchSummary from RefSeq, OMIM, UniProt
DNmechanismAD/ARLOEUF 0.572 OMIM phenotypes
Clinical SummaryPROS1
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Gene-Disease Validity (ClinGen)
protein S deficiency · SDDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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Clinical Trials
3 active or recruiting trials — potential therapeutic options may be available
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GeneReview available — PROS1
Authoritative clinical overview · Recommended first read
Open GeneReview ↗

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint
0.57LOEUF
pLI 0.000
Z-score 3.49
OE 0.35 (0.230.57)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
0.58Z-score
OE missense 0.91 (0.831.00)
335 obs / 366.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.35 (0.230.57)
00.351.4
Missense OE0.91 (0.831.00)
00.61.4
Synonymous OE0.99
01.21.6
LoF obs/exp: 12 / 34.0Missense obs/exp: 335 / 366.5Syn Z: 0.11
DN
0.6453th %ile
GOF
0.5758th %ile
LOF
0.2776th %ile

The highest-scoring mechanism for this gene is dominant-negative.

DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

PROS1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold
Clinical Literature
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