Sudden infant death syndrome: genes and variants
Sudden infant death syndrome is linked to 2 analyzed proteins (SCN5A and CALM2). 3 DNA variants are known to cause it; 14 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Sudden infant death syndrome
SCN5A: Sodium channel protein type 5 subunit alpha
Its rapid inward sodium current drives the upstroke of the cardiac action potential and enables fast electrical conduction through atrial, ventricular, and conduction-system tissue. Pathogenic variants can cause long-QT syndrome type 3, Brugada syndrome, conduction disease, and overlapping arrhythmia phenotypes.
2 disease-causing and 9 uncertain variants in SCN5A are linked to Sudden infant death syndrome.
CALM2: Calmodulin-2
It supplies an identical calmodulin protein that couples changes in intracellular calcium to numerous signaling and ion-channel targets. Pathogenic missense variants can cause calmodulinopathy with malignant ventricular arrhythmias, including long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia.
1 disease-causing and 0 uncertain variants in CALM2 are linked to Sudden infant death syndrome.
Weakly linked (only a few uncertain records): TNNI3, SCN1A, CALM1, DEPDC5, SCN4A, SCN8A and PLN.
Known disease-causing variants in Sudden infant death syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| SCN5A S1710L | 1710 | IV | Disease-causing (★★) |
| SCN5A V1763M | 1763 | IV | Disease-causing (★★) |
| CALM2 G114R | 114 | EF-hand 3 | Disease-causing |
Same protein, different disease
- Brugada syndrome is also caused by SCN5A variants; they fall mostly in different places as the Sudden infant death syndrome variants (24 disease-causing).
- Cardiac arrhythmia is also caused by SCN5A variants; they fall mostly in different places as the Sudden infant death syndrome variants (17 disease-causing).
- Long QT syndrome is also caused by SCN5A variants; they fall mostly in different places as the Sudden infant death syndrome variants (16 disease-causing).
- Dilated cardiomyopathy is also caused by SCN5A variants; they fall mostly in different places as the Sudden infant death syndrome variants (4 disease-causing).
- Progressive familial heart block is also caused by SCN5A variants; they fall mostly in different places as the Sudden infant death syndrome variants (4 disease-causing).
- Long QT syndrome is also caused by CALM2 variants; they fall mostly in different places as the Sudden infant death syndrome variants (21 disease-causing).
Diseases related to Sudden infant death syndrome
- Long QT syndrome, also linked to CALM2 and SCN5A
- Dilated cardiomyopathy, also linked to SCN5A
- Cardiac arrhythmia, also linked to SCN5A
- Primary dilated cardiomyopathy, also linked to SCN5A
- Brugada syndrome, also linked to SCN5A
- Epilepsy, also linked to SCN5A
- Atrial fibrillation, familial, 10, also linked to SCN5A
- Sick sinus syndrome 2, autosomal dominant, also linked to SCN5A
- Progressive familial heart block, also linked to SCN5A
- Ventricular fibrillation, paroxysmal familial, type 1, also linked to SCN5A
Frequently asked questions
Which genes are linked to Sudden infant death syndrome?
In CATVariant, Sudden infant death syndrome is linked to 2 analyzed proteins: SCN5A (Sodium channel protein type 5 subunit alpha) and CALM2 (Calmodulin-2).
How many genetic variants are linked to Sudden infant death syndrome?
24 variants: 3 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 14 are of uncertain significance or have conflicting reports.
Which uncertain variants in Sudden infant death syndrome look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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