CNGB3
Chr 8ARcyclic nucleotide gated channel subunit beta 3
Also known as: ACHM1
This gene encodes the beta subunit of cyclic nucleotide-gated ion channels in cone photoreceptors that mediate phototransduction by converting changes in cGMP levels into electrical signals in response to light. Mutations cause achromatopsia 3, an autosomal recessive condition characterized by complete color blindness, reduced visual acuity, and photophobia affecting central vision from birth. The gene shows very low constraint against loss-of-function variants (pLI near zero), consistent with the recessive inheritance pattern where both copies must be affected to cause disease.
Primary Disease Associations & Inheritance
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Tolerant to missense variation
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
500 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 21 | 0 | 19 | 0 | 40 |
Likely Pathogenic | 28 | 3 | 14 | 0 | 45 |
VUS | 2 | 113 | 14 | 7 | 136 |
Likely Benign | 2 | 5 | 135 | 130 | 272 |
Benign | 0 | 0 | 3 | 0 | 3 |
Conflicting | — | 1 | |||
| Total | 53 | 121 | 185 | 137 | 497 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
CNGB3 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
External Resources
Links to major genomics databases and tools