Is ALG1 p.Thr64Ile (c.191C>T) pathogenic?

ALG1 p.Thr64Ile (c.191C>T) is classified Uncertain significance in ALG1 (ClinVar, Single submitter, 1 submitter; last evaluated 2021-09-01). AlphaMissense: ambiguous (0.4457); Very rare (popmax 8.57e-05%, nfe); Associated with ALG1-congenital disorder of glycosylation.

What condition is associated with ALG1 p.Thr64Ile (c.191C>T)?

ALG1 p.Thr64Ile (c.191C>T) is associated with ALG1-congenital disorder of glycosylation (ClinVar).

How common is ALG1 p.Thr64Ile (c.191C>T) in the general population?

ALG1 p.Thr64Ile (c.191C>T) is very rare (popmax 8.57e-05%, nfe) (gnomAD).

How is ALG1-CDG inherited?

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

What do computational predictors say about ALG1 p.Thr64Ile (c.191C>T)?

AlphaMissense predicts ambiguous (score 0.4457) — an in-silico prediction, not a clinical call.

ALG1 p.Thr64Ile

c.191C>T · rs145474820 · VCV1345840

Uncertain significance Single submitter

Classification

Uncertain significance

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

AlphaMissense

ambiguous

0.4457 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 8.57e-05%, nfe)

Conditions

ALG1-congenital disorder of glycosylation

Computational evidence

Protein change
AlphaMissense	0.4457	ambiguous
REVEL	0.605	indeterminate
SaProt	LLR -11.55	damaging
Splicing
SpliceAI	<0.2	all four deltas below 0.2 · C>G here scores Δ0.87 · evaluated, not missing
Constraint at this position
Conservation	phyloP 3.9	GERP 1.3, phastCons 1
Regional constraint	o/e 1.27	unconstrained · MANE · 13 kb · p 3.2e-11 · regional, not allelic
Overall
CADD	25.5	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 8.57e-05% European (non-Finnish) · 1/1,166,892 alleles

Overall 0.000126% 2/1,587,768 alleles · very rare exomes 2/1,436,550 · genomes 0/151,218 · joint denominator

Ancestry group	Frequency	1 in
Remaining individualsnot grpmax-eligible	0.00163%	61,476
European (non-Finnish)grpmax	8.57e-05%	1,166,892

Remaining individuals shows a higher raw frequency than the grpmax group above it. gnomAD excludes bottlenecked groups — Finnish, Ashkenazi Jewish, Amish and “Remaining individuals” — from grpmax, because founder effects make their frequencies unrepresentative for filtering. The table is sorted by frequency, so an excluded group can sit above the grpmax row.

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: ALG1
Protein: p.Thr64Ile
Coding: c.191C>T
MANE Select: NM_019109
dbSNP: rs145474820
Type: single nucleotide variant
Location: chr16:5072040 (GRCh38)
Gene constraint: LOEUF 1.419 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 93.24

Full ALG1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

ALG1-congenital disorder of glycosylation — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For ALG1-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

ALG1 c.1187+1G>A Pathogenic/Likely pathogenic ★★ same condition
ALG1 c.1187+2T>C Pathogenic ★★ same condition
ALG1 c.1188-2A>G Pathogenic/Likely pathogenic ★★ same condition
ALG1 c.209-2A>G Likely pathogenic ★★ same condition
ALG1 c.539+1G>A Pathogenic/Likely pathogenic ★★ same condition
ALG1 c.630-2A>G Likely pathogenic ★★ same condition
ALG1 c.863-2A>G Likely pathogenic ★★ same condition
ALG1 c.961+1G>A 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/alg1-p-thr64ile (accessed [today's date]).

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