Is RUNX1 p.Pro42= (c.126G>A) pathogenic?

RUNX1 p.Pro42= (c.126G>A) is classified Likely benign in RUNX1 (ClinVar, Expert panel, 3 submitters; last evaluated 2026-05-04). Very rare (popmax 0.0011%, sas); Associated with hereditary thrombocytopenia and hematologic cancer predisposition syndrome.

What condition is associated with RUNX1 p.Pro42= (c.126G>A)?

RUNX1 p.Pro42= (c.126G>A) is associated with hereditary thrombocytopenia and hematologic cancer predisposition syndrome, hereditary thrombocytopenia and hematological cancer predisposition syndrome associated with RUNX1 (ClinVar).

How common is RUNX1 p.Pro42= (c.126G>A) in the general population?

RUNX1 p.Pro42= (c.126G>A) is very rare (popmax 0.0011%, sas) (gnomAD).

RUNX1 p.Pro42=

Q: How is Familial platelet disorder with associated myeloid malignancy inherited?

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

c.126G>A · rs1228331250 · VCV2831823

Likely benign Expert panel

Classification

Likely benign

ClinVar

Review

Expert panel ★★★☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

very rare (popmax 0.0011%, sas)

Conditions

hereditary thrombocytopenia and hematologic cancer predisposition syndrome

ClinGen expert panel — Myeloid Malignancy VCEP

Likely Benign for hereditary thrombocytopenia and hematologic cancer predisposition syndrome. Applied ACMG criteria (verbatim):

PM2_Supporting BP7 BP4

Curation rationale (ClinGen, verbatim)

NM_001754.5(RUNX1):c.126G>A (p.Pro42=) is a synonymous variant which has a SpliceAI score ≤ 0.20 (0.01) (BP4, BP7). This variant is completely absent from all population databases with at least 20x coverage for RUNX1 (PM2_supporting). In summary, this variant meets criteria to be classified as likely benign. ACMG/AMP criteria applied, as specified by the Myeloid Malignancy Variant Curation Expert Panel for RUNX1: BP4, BP7, PM2_supporting.

ClinGen Evidence Repository → · reported verbatim, not re-tallied by Sugi Variant.

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 3.2	GERP -0.28, phastCons 1
Overall
CADD	16.28	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0011% South Asian · 1/91,070 alleles

Overall 6.25e-05% 1/1,598,994 alleles · very rare exomes 0/1,446,812 · genomes 1/152,182 · joint denominator

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: RUNX1
Protein: p.Pro42=
Coding: c.126G>A
MANE Select: NM_001754
dbSNP: rs1228331250
Type: single nucleotide variant
Location: chr21:34887068 (GRCh38)
Gene constraint: LOEUF 0.633 · pLI 0.29 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 61.76 · 5 PDB

Full RUNX1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

hereditary thrombocytopenia and hematologic cancer predisposition syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary thrombocytopenia and hematological cancer predisposition syndrome associated with RUNX1

For Familial platelet disorder with associated myeloid malignancy (Orphanet):

Inheritance: Autosomal dominant

Similar variants

RUNX1 p.Pro42Gln Uncertain significance ★★★ ⚠ same residue
RUNX1 p.Pro42Leu Uncertain significance ★★★ ⚠ same residue
RUNX1 c.351+1G>A Pathogenic ★★★ same condition
RUNX1 c.351+1G>C Likely pathogenic ★★★ same condition
RUNX1 c.351+1G>T Pathogenic ★★★ same condition
RUNX1 c.351+2T>A Likely pathogenic ★★★ same condition
RUNX1 c.351+2T>C Likely pathogenic ★★★ same condition
RUNX1 c.352-1G>A Pathogenic ★★★ 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/runx1-p-pro42 (accessed [today's date]).

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