Is AGL p.Ala253= (c.759A>G) pathogenic?

AGL p.Ala253= (c.759A>G) is classified Likely benign in AGL (ClinVar, Single submitter, 1 submitter; last evaluated 2025-11-13). Very rare (popmax 0.000169%, nfe); Associated with glycogen storage disease III.

What condition is associated with AGL p.Ala253= (c.759A>G)?

AGL p.Ala253= (c.759A>G) is associated with glycogen storage disease III (ClinVar).

How common is AGL p.Ala253= (c.759A>G) in the general population?

AGL p.Ala253= (c.759A>G) is very rare (popmax 0.000169%, nfe) (gnomAD).

AGL p.Ala253=

Q: How is Glycogen storage disease due to glycogen debranching enzyme deficiency inherited?

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

c.759A>G · VCV4731149

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.000169%, nfe)

Conditions

glycogen storage disease III

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 -0.59	GERP -3.5
Overall
CADD	4.083	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.000169% European (non-Finnish) · 2/1,179,964 alleles

Filtering AF 2.8e-05% ClinGen BA1/BS1 input FAF95, joint · FAF99 1.1e-05%

Overall 0.000137% 2/1,461,752 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: AGL
Protein: p.Ala253=
Coding: c.759A>G
MANE Select: NM_000642
Type: single nucleotide variant
Location: chr1:99870494 (GRCh38)
Gene constraint: LOEUF 0.72 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 92.88 · 1 PDB
Residue 253: the 'amylo-1,6-glucosidase' region; an α-helix

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

Disease context

glycogen storage disease III — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Glycogen storage disease due to glycogen debranching enzyme deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Childhood, Infancy
Prevalence: 1-9 / 100 000 (United States)

Similar variants

AGL p.Ala253Pro Uncertain significance ★★ ⚠ same residue
AGL p.Ala253Gly Uncertain significance ★ ⚠ same residue
AGL p.Ala253Ser Uncertain significance ★ ⚠ same residue
AGL c.1283+2T>C Likely pathogenic ★★ same condition
AGL c.1284-1G>A Likely pathogenic ★★ same condition
AGL c.1284-2A>G Likely pathogenic ★★ same condition
AGL c.1423+1G>A Pathogenic ★★ same condition
AGL c.1423+1G>C 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/agl-p-ala253 (accessed [today's date]).

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