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PYGM p.Ala55fs

c.164_168del · rs780193588 · VCV945649

Pathogenic Multiple submitters
Classification
Pathogenic
ClinVar
Review
Multiple submitters ★★☆☆
ClinVar · 5 submitters
Consequence
frameshift
predicted LoF
gnomAD v4.1
Rare
very rare (popmax 0.00167%, amr)
Conditions
1
glycogen storage disease V

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequenceframeshiftpredicted loss-of-function
NMDpredictedpremature termination codon in exon 1 of 20
Splicing
SpliceAI—not assessed · substitutions only
Constraint at this position
ConservationphyloP 7.7GERP 1.8, phastCons 1
Overall
CADD35.0PHRED · no single calibrated threshold — expert panels disagree

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

gnomAD v4.1 · exomes + genomes
Grpmax group 0.00167% Admixed American · 1/60,014 alleles
Filtering AF 0.000124% ClinGen BA1/BS1 input FAF95, joint · FAF99 9e-05%
Overall 0.000496% 8/1,614,092 alleles · very rare
Ancestry group Frequency 1 in
Remaining individualsnot grpmax-eligible 0.0032% 31,242
Admixed Americangrpmax 0.00167% 60,014
European (non-Finnish) 0.000424% 236,008

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
PYGM
Protein
p.Ala55fs
Coding
c.164_168del
MANE Select
NM_005609
dbSNP
rs780193588
Type
Deletion
Location
chr11:64759731 (GRCh38)
Gene constraint
LOEUF 0.962 · pLI <0.01 (gnomAD)
Structure
AlphaFold pLDDT 94.41 · 1 PDB
Residue 55
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

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-ala55fs (accessed [today's date]).

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