SCN5A Variant R222X

Summary of observed carriers, functional annotations, and structural context for SCN5A R222X. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT3 penetrance

4%

2/63 effective observations

Estimated BrS1 penetrance

57%

35/63 effective observations

Total carriers

53

33 BrS1 · 1 LQT3 · 19 unaffected

R222X has not been reported in gnomAD. This residue resides in a Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQT3.

Variant features alone are equivalent to phenotyping 2 individuals for Brugada syndrome and 1 individuals for LQT3.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 28 30

PROVEAN scores below -2 suggest deleterious impact. REVEL scores above 0.5–0.75 are often interpreted as likely pathogenic. PolyPhen-2 scores above 0.85 are typically pathogenic. Penetrance density summarises neighbouring residue risk (Kroncke et al. 2019).

Reported carrier data

Observed carriers by publication or cohort.
Source Year Carriers Unaffected LQT3 BrS1 Other Other Disease
27287068 2016 2 0 2 0
22277643 2012 38 0 25 0
26173111 2015 1 0 1 0
26467377 2016 7 0 1 0
27232914 2016 1 0 1 0
19716085 2009 1 1 0 0
20129283 2010 4 0 4 0
29325976 2018 2 0 2 0
Literature, cohort, and gnomAD 53 19 1 33
Variant features alone 15 12 1 2

Totals may differ from individual publications due to duplicate patients removed during curation.

Functional data

Peak and late/persistent current values are relative to wild-type (100% indicates no change). V1/2 activation and inactivation denote the membrane potentials (mV) at which half-maximal current is achieved.

Published electrophysiology measurements.
PubMed ID Year Cell Type Peak Current (% WT) V1/2 Activation (mV) V1/2 Inactivation (mV) Late/Persistent Current (% WT)
27287068 2016 Oocytes 0
22277643 2012
26173111 2015
26467377 2016
27232914 2016
19716085 2009
20129283 2010
29325976 2018