Is F2 p.Ala277= (c.831C>T) pathogenic?

F2 p.Ala277= (c.831C>T) is classified Likely benign in F2 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2024-10-14). Ultra-rare (popmax 0.0111%, eas); Associated with congenital prothrombin deficiency.

What condition is associated with F2 p.Ala277= (c.831C>T)?

F2 p.Ala277= (c.831C>T) is associated with congenital prothrombin deficiency (ClinVar).

How common is F2 p.Ala277= (c.831C>T) in the general population?

F2 p.Ala277= (c.831C>T) is ultra-rare (popmax 0.0111%, eas) (gnomAD).

How is Congenital factor II deficiency inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

F2 p.Ala277=

c.831C>T · rs758385055 · VCV2895957

Likely benign Multiple submitters

Classification

Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0111%, eas)

Conditions

congenital prothrombin deficiency

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -15	GERP -3.5
Overall
CADD	0.122	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0111% East Asian · 5/44,896 alleles

Filtering AF 0.00434% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00276%

Overall 0.00161% 26/1,613,994 alleles · ultra-rare exomes 24/1,461,820 · genomes 2/152,174 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.0111%	8,979
Admixed American	0.005%	20,000
European (non-Finnish)	0.00136%	73,753
African / African-American	0.00133%	74,914
South Asian	0.0011%	91,086

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: F2
Protein: p.Ala277=
Coding: c.831C>T
MANE Select: NM_000506
dbSNP: rs758385055
Type: single nucleotide variant
Location: chr11:46726130 (GRCh38)
Gene constraint: LOEUF 0.552 · pLI 0.15 (gnomAD)
Structure: AlphaFold pLDDT 84.37 · 480 PDB
Residue 277: a β-strand; the kringle 2 domain

Full F2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

congenital prothrombin deficiency — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Congenital factor II deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: All ages
Prevalence: <1 / 1 000 000 (Europe)

Similar variants

F2 p.Arg461Trp Pathogenic/Likely pathogenic ★★ same condition
F2 p.Arg500Gln Pathogenic ★★ ⚠ same condition
F2 p.Arg581Cys Pathogenic/Likely pathogenic ★★ same condition
F2 p.Arg596Gln Pathogenic ★★ ⚠ same condition
F2 p.Gln387Ter Pathogenic/Likely pathogenic ★★ same condition
F2 c.559+5G>A Uncertain significance ★★ same condition
F2 p.Ala17Ser Uncertain significance ★★ ⚠ same condition
F2 p.Arg124Gln Uncertain significance ★★ ⚠ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/f2-p-ala277 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown