Is PYGM p.Ile440= (c.1320C>A) pathogenic?

PYGM p.Ile440= (c.1320C>A) is classified Likely benign in PYGM (ClinVar, Single submitter, 1 submitter; last evaluated 2022-06-27). Absent from gnomAD v4.1; Associated with glycogen storage disease V.

What condition is associated with PYGM p.Ile440= (c.1320C>A)?

PYGM p.Ile440= (c.1320C>A) is associated with glycogen storage disease V (ClinVar).

How common is PYGM p.Ile440= (c.1320C>A) in the general population?

PYGM p.Ile440= (c.1320C>A) is absent from gnomAD v4.1 (gnomAD).

PYGM p.Ile440=

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.1320C>A · rs2135833170 · VCV2011348

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Not reported

no allele count reported in gnomAD v4.1 (AN 1,608,692)

Conditions

glycogen storage disease V

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 6.2	GERP 0.91, phastCons 1
Overall
CADD	12.47	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

No allele count reported in gnomAD v4.1 (AN 1,608,692). This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: PYGM
Protein: p.Ile440=
Coding: c.1320C>A
MANE Select: NM_005609
dbSNP: rs2135833170
Type: single nucleotide variant
Location: chr11:64753602 (GRCh38)
Gene constraint: LOEUF 0.962 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 94.41 · 1 PDB
Residue 440: a UniProt-annotated variant site (in gsd5); a β-strand

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 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
PYGM c.1768+1G>A Pathogenic/Likely pathogenic ★★ same condition
PYGM c.1768+2T>G Pathogenic/Likely pathogenic ★★ same condition
PYGM c.1827+1G>C 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/pygm-p-ile440 (accessed [today's date]).

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