SCN5A Variant V300I

Summary of observed carriers, functional annotations, and structural context for SCN5A V300I. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT3 penetrance

5%

0/12 effective observations

Estimated BrS1 penetrance

27%

3/12 effective observations

Total carriers

2

1 BrS1 · 0 LQT3 · 1 unaffected

V300I is present in 1 alleles in gnomAD. This residue resides in a Mild_Hotspot region for Brugada syndrome and a Non_Hotspot region for LQT3.

Variant features alone are equivalent to phenotyping 2 individuals for Brugada syndrome and 0 individuals for LQT3.

In silico predictors

Variant-level computational predictors.
PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.18 0 -1.66 0.516 26 0

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
20129283 2010 1 0 1 0
Literature, cohort, and gnomAD 2 1 0 1
Variant features alone 15 13 0 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)
20129283 2010

Nearby variants

Neighbouring residues within 15 Ångström provide structural context. Variants listed in the right-most column have been observed clinically or in gnomAD.

Previously observed variants near V300I.
Neighbour residue Distance (Å) Observed variants
285 15 T285K,
286 14 A286S, A286V,
287 14
288 13 N288S,
289 13 G289S,
290 12 p.T290_G292del,
291 11 N291S, N291H, p.N291_S293dup, N291K, p.N291TfsX52, N291K,
292 11 G292S,
293 10
294 9 V294M,
295 8 E295K,
296 8
297 7
298 5 G298S, G298D,
299 4 L299F, L299M, L299F,
300 0 V300I,
301 4
302 5
303 7
304 8
305 8 D305N
306 9 L306F, L306V,
307 10
308 11
309 11 S309C, S309N,
310 12 D310N,
311 13
312 13 E312K, c.934+1G>A, c.934+4C>T,
313 14
314 14
315 15 L315P,