Is KIT p.Cys443= (c.1329T>C) pathogenic?

KIT p.Cys443= (c.1329T>C) is classified Benign/Likely benign in KIT (ClinVar, Multiple submitters, 3 submitters; last evaluated 2026-06-03). Very rare (popmax 0.00223%, eas); Associated with gastrointestinal stromal tumor.

What condition is associated with KIT p.Cys443= (c.1329T>C)?

KIT p.Cys443= (c.1329T>C) is associated with gastrointestinal stromal tumor, hereditary neoplastic syndrome (ClinVar).

How common is KIT p.Cys443= (c.1329T>C) in the general population?

KIT p.Cys443= (c.1329T>C) is very rare (popmax 0.00223%, eas) (gnomAD).

How is Gastrointestinal stromal tumor inherited?

Typically Autosomal dominant, Not applicable (Orphanet). A genetic counselor can assess individual risk for a family.

KIT p.Cys443=

c.1329T>C · rs768900424 · VCV1090073

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Conditions

gastrointestinal stromal tumor

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 2.4	GERP 0.23, phastCons 1
Overall
CADD	8.678	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00223% East Asian · 1/44,862 alleles

Overall 6.86e-05% 1/1,458,464 alleles · very rare

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: KIT
Protein: p.Cys443=
Coding: c.1329T>C
MANE Select: NM_000222
dbSNP: rs768900424
Type: single nucleotide variant
Location: chr4:54723681 (GRCh38)
Gene constraint: LOEUF 0.24 · pLI 1.00 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 78.52 · 65 PDB
Residue 443: a β-strand; a disulfide bond; the ig-like c2-type 5 domain

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

Disease context

gastrointestinal stromal tumor — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary neoplastic syndrome

For Gastrointestinal stromal tumor (Orphanet):

Inheritance: Autosomal dominant, Not applicable
Onset: Adolescent, Adult, Childhood
Prevalence: 1-5 / 10 000 (Europe)

Similar variants

KIT p.Cys443Ser Uncertain significance ★★ ⚠ same residue
KIT p.Ala621Thr Pathogenic/Likely pathogenic ★★ same condition
KIT p.Asp820Tyr Pathogenic ★★ same condition
KIT p.Gln190Ter Pathogenic ★★ same condition
KIT p.Leu576Pro Pathogenic/Likely pathogenic ★★ same condition
KIT p.Lys642Glu Pathogenic ★★ same condition
KIT p.Trp557Arg Pathogenic/Likely pathogenic ★★ same condition
KIT p.Val559Ala Pathogenic/Likely 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/kit-p-cys443 (accessed [today's date]).

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