Is CRPPA p.Val166= (c.498C>A) pathogenic?

CRPPA p.Val166= (c.498C>A) is classified Likely benign in CRPPA (ClinVar, Single submitter, 1 submitter; last evaluated 2022-08-02). Very rare (popmax 0.00834%, amr); Associated with muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7.

How common is CRPPA p.Val166= (c.498C>A) in the general population?

CRPPA p.Val166= (c.498C>A) is very rare (popmax 0.00834%, amr) (gnomAD).

How is Walker-Warburg syndrome inherited?

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

CRPPA p.Val166=

Q: What condition is associated with CRPPA p.Val166= (c.498C>A)?

CRPPA p.Val166= (c.498C>A) is associated with muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7, autosomal recessive limb-girdle muscular dystrophy type 2U (ClinVar).

c.498C>A · rs774132708 · VCV1680788

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00834%, amr)

Conditions

muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7

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 -0.077	GERP -4.8, phastCons 0.1
Overall
CADD	1.234	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00834% Admixed American · 5/59,970 alleles

Filtering AF 0.00323% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00207%

Overall 0.000372% 6/1,613,668 alleles · very rare exomes 5/1,461,528 · genomes 1/152,140 · joint denominator

Ancestry group	Frequency	1 in
Admixed Americangrpmax	0.00834%	11,994
Remaining individualsnot grpmax-eligible	0.0016%	62,464

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: CRPPA
Protein: p.Val166=
Coding: c.498C>A
MANE Select: NM_001101426
dbSNP: rs774132708
Type: single nucleotide variant
Location: chr7:16406097 (GRCh38)
Gene constraint: LOEUF 1.462 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 88.63 · 1 PDB
Residue 166: an α-helix

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

Disease context

muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A, 7 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: autosomal recessive limb-girdle muscular dystrophy type 2U

For Walker-Warburg syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Antenatal, Infancy, Neonatal
Prevalence: <1 / 1 000 000 (United Kingdom)

Similar variants

CRPPA p.Val166Ile Uncertain significance ★ ⚠ same residue
CRPPA p.Val166Asp Uncertain significance ★ ⚠ same residue
CRPPA c.1120-1G>T Pathogenic ★★ same condition
CRPPA c.258-1G>C Pathogenic/Likely pathogenic ★★ same condition
CRPPA c.835+2T>C Pathogenic/Likely pathogenic ★★ same condition
CRPPA p.Arg184Ter Pathogenic ★★ same condition
CRPPA p.Arg268Ter Pathogenic ★★ same condition
CRPPA p.Gln215Ter Pathogenic/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/crppa-p-val166 (accessed [today's date]).

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