Is MITF p.Pro256Thr (c.766C>A) pathogenic?

MITF p.Pro256Thr (c.766C>A) is classified Uncertain significance in MITF (ClinVar, Multiple submitters, 3 submitters; last evaluated 2026-04-03). AlphaMissense: likely pathogenic (0.6661); Very rare (popmax 6.85e-05%); Associated with Tietz syndrome.

What condition is associated with MITF p.Pro256Thr (c.766C>A)?

MITF p.Pro256Thr (c.766C>A) is associated with Tietz syndrome, Waardenburg syndrome type 2A, melanoma, cutaneous malignant, susceptibility to, 8 (ClinVar).

How common is MITF p.Pro256Thr (c.766C>A) in the general population?

MITF p.Pro256Thr (c.766C>A) is very rare (popmax 6.85e-05%) (gnomAD).

What do computational predictors say about MITF p.Pro256Thr (c.766C>A)?

AlphaMissense predicts likely pathogenic (score 0.6661) — an in-silico prediction, not a clinical call.

MITF p.Pro256Thr

c.766C>A · rs980918814 · VCV2115672

Uncertain significance Multiple submitters

Classification

Uncertain significance

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 3 submitters

AlphaMissense

likely pathogenic

0.6661 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 6.85e-05%)

Missense predictors

1/2 damaging

AlphaMissense, SaProt · REVEL no call

Conditions

Tietz syndrome

Computational evidence

Protein change
AlphaMissense	0.6661	likely pathogenic
REVEL	0.369	indeterminate
SaProt	LLR -8.37	tolerated
⇒ AlphaMissense calls this damaging; SaProt does not; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.7	GERP 2.1, phastCons 1
Regional constraint	o/e 0.96	unconstrained · MANE · 14 kb · p 0.51 · regional, not allelic
Overall
CADD	26.2	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 6.85e-05%

Overall 6.85e-05% 1/1,459,688 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: MITF
Protein: p.Pro256Thr
Coding: c.766C>A
MANE Select: NM_001354604
dbSNP: rs980918814
Type: single nucleotide variant
Location: chr3:69949054 (GRCh38)
Gene constraint: LOEUF 0.482 · pLI 0.99 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 62.25 · 12 PDB
Residue 256: the 'transactivation' region

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

Disease context

Tietz syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: Waardenburg syndrome type 2A melanoma, cutaneous malignant, susceptibility to, 8 hereditary neoplastic syndrome

Similar variants

MITF p.Pro256= Likely benign ★★ same residue
MITF c.1031+1G>A Pathogenic ★★ same condition
MITF c.1179+1G>A Pathogenic ★★ same condition
MITF c.355-1062G>C Pathogenic/Likely pathogenic ★★ same condition
MITF c.880+1G>A Likely pathogenic ★★ same condition
MITF c.955+1G>A Likely pathogenic ★★ same condition
MITF c.956-1G>A Pathogenic ★★ same condition
MITF p.Arg217Ter 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/mitf-p-pro256thr (accessed [today's date]).

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