Is CALM3 p.Ala74= (c.222C>A) pathogenic?

CALM3 p.Ala74= (c.222C>A) is classified Likely benign in CALM3 (ClinVar, Single submitter, 1 submitter; last evaluated 2024-02-29). Absent from gnomAD v4.1; Associated with long QT syndrome 1.

What condition is associated with CALM3 p.Ala74= (c.222C>A)?

CALM3 p.Ala74= (c.222C>A) is associated with long QT syndrome 1 (ClinVar).

How common is CALM3 p.Ala74= (c.222C>A) in the general population?

CALM3 p.Ala74= (c.222C>A) is absent from gnomAD v4.1 (gnomAD).

How is Romano-Ward syndrome inherited?

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

CALM3 p.Ala74=

c.222C>A · VCV3643757

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Absent

absent from gnomAD v4.1

Conditions

long QT syndrome 1

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 0.1	GERP -3.7, phastCons 0.94
Overall
CADD	12.54	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: CALM3
Protein: p.Ala74=
Coding: c.222C>A
MANE Select: NM_005184
Type: single nucleotide variant
Location: chr19:46608525 (GRCh38)
Gene constraint: LOEUF 0.556 · pLI 0.93 · ClinGen HI 0/3 (gnomAD)
Structure: AlphaFold pLDDT 85.45 · 26 PDB
Residue 74: the ef-hand 2 domain; an α-helix

Full CALM3 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

long QT syndrome 1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For Romano-Ward syndrome (Orphanet):

Inheritance: Autosomal dominant, Autosomal recessive
Onset: All ages
Prevalence: 1-5 / 10 000 (Europe)

Similar variants

CALM3 p.Asp94Ala Pathogenic/Likely pathogenic ★★ same condition
CALM3 p.Asp96His Pathogenic/Likely pathogenic ★★ same condition
CALM3 p.Glu141Lys Pathogenic ★★ same condition
CALM3 c.34+3G>A Uncertain significance ★★ same condition
CALM3 c.421+5G>A Uncertain significance ★★ same condition
CALM3 p.Ala148Thr Uncertain significance ★★ ⚠ same condition
CALM3 p.Arg107Cys Uncertain significance ★★ ⚠ same condition
CALM3 p.Asp132Asn 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/calm3-p-ala74 (accessed [today's date]).

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