Is PYGM p.Ala448= (c.1344G>A) pathogenic?

PYGM p.Ala448= (c.1344G>A) is classified Likely benign in PYGM (ClinVar, Single submitter, 1 submitter; last evaluated 2025-05-10). Very rare (popmax 0.00224%, eas); Associated with glycogen storage disease V.

What condition is associated with PYGM p.Ala448= (c.1344G>A)?

PYGM p.Ala448= (c.1344G>A) is associated with glycogen storage disease V (ClinVar).

How common is PYGM p.Ala448= (c.1344G>A) in the general population?

PYGM p.Ala448= (c.1344G>A) is very rare (popmax 0.00224%, eas) (gnomAD).

PYGM p.Ala448=

Q: How is Glycogen storage disease due to muscle glycogen phosphorylase deficiency inherited?

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

c.1344G>A · rs1466751658 · VCV1135239

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00224%, eas)

Conditions

glycogen storage disease V

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation/SpliceAI carries the signal.
Splicing
SpliceAI	Δ0.98	acceptor gain · deltas
Pangolin	Δ0.32	gain · loss 0.00 · agrees with SpliceAI · independent
Constraint at this position
Conservation	phyloP -10	GERP -3.9
Overall
CADD	21.0	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00224% East Asian · 1/44,644 alleles

Filtering AF 0.000368% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000138%

Overall 0.000436% 7/1,605,694 alleles · very rare exomes 6/1,453,416 · genomes 1/152,278 · joint denominator

Ancestry group	Frequency	1 in
East Asiangrpmax	0.00224%	44,644
South Asian	0.00222%	45,114
European (non-Finnish)	0.00034%	294,551

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: PYGM
Protein: p.Ala448=
Coding: c.1344G>A
MANE Select: NM_005609
dbSNP: rs1466751658
Type: single nucleotide variant
Location: chr11:64753578 (GRCh38)
Gene constraint: LOEUF 0.962 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 94.41 · 1 PDB
Residue 448: a UniProt-annotated variant site (in gsd5); an α-helix

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

Disease context

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

For Glycogen storage disease due to muscle glycogen phosphorylase deficiency (Orphanet):

Inheritance: Autosomal recessive
Onset: Adolescent, Adult, Childhood

Similar variants

PYGM p.Ala448Thr Uncertain significance ★★ ⚠ same residue
PYGM p.Ala448Val Uncertain significance ★★ ⚠ same residue
PYGM p.Ala448fs Pathogenic ★ same residue
PYGM c.1092+1G>A Likely pathogenic ★★ same condition
PYGM c.1092+1G>C Likely pathogenic ★★ same condition
PYGM c.1239+1G>A Pathogenic/Likely pathogenic ★★ same condition
PYGM c.1240-2A>G Likely pathogenic ★★ same condition
PYGM c.1403+1G>A 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/pygm-p-ala448 (accessed [today's date]).

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