Is MTTP p.Arg644Lys (c.1931G>A) pathogenic?

MTTP p.Arg644Lys (c.1931G>A) is classified Uncertain significance in MTTP (ClinVar, Single submitter, 1 submitter; last evaluated 2021-08-26). AlphaMissense: ambiguous (0.5102); Absent from gnomAD v4.1.

How common is MTTP p.Arg644Lys (c.1931G>A) in the general population?

MTTP p.Arg644Lys (c.1931G>A) is absent from gnomAD v4.1 (gnomAD).

What do computational predictors say about MTTP p.Arg644Lys (c.1931G>A)?

AlphaMissense predicts ambiguous (score 0.5102) — an in-silico prediction, not a clinical call.

MTTP p.Arg644Lys

c.1931G>A · rs1725951559 · VCV964452

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.5102 · ACMG-weighted

gnomAD v4.1

Absent

absent from gnomAD v4.1

Missense predictors

0/2 damaging

REVEL, SaProt · AlphaMissense no call

Computational evidence

Protein change
AlphaMissense	0.5102	ambiguous
REVEL	0.185	benign-leaning
SaProt	LLR -8.70	tolerated
⇒ REVEL and SaProt both call this tolerated; AlphaMissense makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 12	GERP 1.5, phastCons 1
Regional constraint	o/e 0.89	unconstrained · MANE · 48 kb · p 0.00018 · regional, not allelic
Overall
CADD	25.2	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

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: MTTP
Protein: p.Arg644Lys
Coding: c.1931G>A
MANE Select: NM_001386140
dbSNP: rs1725951559
Type: single nucleotide variant
Location: chr4:99611395 (GRCh38)
Gene constraint: LOEUF 0.672 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 86.73 · 2 PDB
Residue 644: the vitellogenin domain; a β-strand

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

Similar variants

MTTP p.Arg644= Likely benign ★ same residue
MTTP c.1067+1G>C Likely pathogenic ★★ same type
MTTP c.1236+1G>A Pathogenic/Likely pathogenic ★★ same type
MTTP c.1769+2T>C Pathogenic/Likely pathogenic ★★ same type
MTTP c.1867+1G>A Pathogenic ★★ same type
MTTP c.1867+5G>A Pathogenic/Likely pathogenic ★★ same type
MTTP c.1868-2A>G Likely pathogenic ★★ same type
MTTP c.2342+1G>A Pathogenic ★★ same type

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/mttp-p-arg644lys (accessed [today's date]).

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