Is LARGE1 p.Ser33= (c.99C>T) pathogenic?

LARGE1 p.Ser33= (c.99C>T) is classified Conflicting classifications of pathogenicity in LARGE1 (ClinVar, Conflicting submitters, 4 submitters; last evaluated 2026-01-20). Very rare (popmax 0.00823%, nfe); Associated with muscular dystrophy-dystroglycanopathy type B6.

What condition is associated with LARGE1 p.Ser33= (c.99C>T)?

LARGE1 p.Ser33= (c.99C>T) is associated with muscular dystrophy-dystroglycanopathy type B6, muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A6 (ClinVar).

How common is LARGE1 p.Ser33= (c.99C>T) in the general population?

LARGE1 p.Ser33= (c.99C>T) is very rare (popmax 0.00823%, nfe) (gnomAD).

LARGE1 p.Ser33=

c.99C>T · rs377353667 · VCV704457

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 4 submitters

gnomAD v4.1

Rare

very rare (popmax 0.00823%, nfe)

Conditions

muscular dystrophy-dystroglycanopathy type B6

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 7.4	GERP 1.8, phastCons 1
Overall
CADD	12.63	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00823% European (non-Finnish) · 97/1,179,240 alleles

Filtering AF 0.00689% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00634%

Overall 0.00632% 102/1,612,880 alleles · very rare exomes 92/1,461,102 · genomes 10/151,778 · joint denominator

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.00823%	12,157
Remaining individualsnot grpmax-eligible	0.0032%	31,228
South Asian	0.0022%	45,528
African / African-American	0.00134%	74,760

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: LARGE1
Protein: p.Ser33=
Coding: c.99C>T
MANE Select: NM_133642
dbSNP: rs377353667
Type: single nucleotide variant
Location: chr22:33761378 (GRCh38)
Gene constraint: LOEUF 0.606 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 86.15 · 4 PDB

Full LARGE1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

muscular dystrophy-dystroglycanopathy type B6 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A6

Similar variants

LARGE1 p.Ser33fs Pathogenic ★ same residue
LARGE1 p.Ser33Asn Uncertain significance ★ ⚠ same residue
LARGE1 p.Arg95Ter Pathogenic ★★ same condition
LARGE1 p.Glu509Lys Pathogenic/Likely pathogenic ★★ same condition
LARGE1 c.*155C>T Uncertain significance ★★ same condition
LARGE1 p.Ala149Ser Uncertain significance ★★ ⚠ same condition
LARGE1 p.Ala252Val Uncertain significance ★★ ⚠ same condition
LARGE1 p.Ala478Thr Uncertain significance ★★ ⚠ 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/large1-p-ser33 (accessed [today's date]).

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