Is ALG6 p.Thr374Ile (c.1121C>T) pathogenic?

ALG6 p.Thr374Ile (c.1121C>T) is classified Uncertain significance in ALG6 (ClinVar, Single submitter, 1 submitter; last evaluated 2021-10-08). AlphaMissense: likely benign (0.2067); Very rare (popmax 0.00442%, sas); Associated with ALG6-congenital disorder of glycosylation 1C.

What condition is associated with ALG6 p.Thr374Ile (c.1121C>T)?

ALG6 p.Thr374Ile (c.1121C>T) is associated with ALG6-congenital disorder of glycosylation 1C (ClinVar).

How common is ALG6 p.Thr374Ile (c.1121C>T) in the general population?

ALG6 p.Thr374Ile (c.1121C>T) is very rare (popmax 0.00442%, sas) (gnomAD).

How is ALG6-CDG inherited?

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

What do computational predictors say about ALG6 p.Thr374Ile (c.1121C>T)?

AlphaMissense predicts likely benign (score 0.2067) — an in-silico prediction, not a clinical call.

ALG6 p.Thr374Ile

c.1121C>T · rs750443322 · VCV2194698

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

likely benign

0.2067 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00442%, sas)

Missense predictors

1/2 damaging

AlphaMissense, SaProt · REVEL no call

Conditions

ALG6-congenital disorder of glycosylation 1C

Computational evidence

Protein change
AlphaMissense	0.2067	likely benign
REVEL	0.455	indeterminate
SaProt	LLR -10.45	damaging
⇒ SaProt calls this damaging; AlphaMissense does not; REVEL makes no call.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 7.6	GERP 1.8, phastCons 1
Regional constraint	o/e 0.86	unconstrained · MANE · 66 kb · p 0.00074 · regional, not allelic
Overall
CADD	23.1	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 0.00442% South Asian · 4/90,424 alleles

Filtering AF 0.00208% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00184%

Overall 0.00236% 38/1,607,342 alleles · very rare

Ancestry group	Frequency	1 in
South Asiangrpmax	0.00442%	22,606
European (non-Finnish)	0.00289%	34,560

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: ALG6
Protein: p.Thr374Ile
Coding: c.1121C>T
MANE Select: NM_013339
dbSNP: rs750443322
Type: single nucleotide variant
Location: chr1:63428795 (GRCh38)
Gene constraint: LOEUF 0.892 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 93.08

Full ALG6 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

ALG6-congenital disorder of glycosylation 1C — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For ALG6-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

ALG6 p.Thr374Ala Uncertain significance ★★ ⚠ same residue
ALG6 c.1128-1G>A Likely pathogenic ★★ same condition
ALG6 c.1128-2A>C Likely pathogenic ★★ same condition
ALG6 c.1326+1G>A Pathogenic/Likely pathogenic ★★ same condition
ALG6 c.257+5G>A Pathogenic/Likely pathogenic ★★ same condition
ALG6 c.429+1G>T Likely pathogenic ★★ same condition
ALG6 c.495-2A>G Likely pathogenic ★★ same condition
ALG6 c.495-2A>T 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/alg6-p-thr374ile (accessed [today's date]).

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