SCN5A Variant V263I

Summary of observed carriers, functional annotations, and structural context for SCN5A V263I. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT3 penetrance

27%

2/13 effective observations

Estimated BrS1 penetrance

2%

0/13 effective observations

Total carriers

3

0 BrS1 · 1 LQT3 · 2 unaffected

V263I is present in 2 alleles in gnomAD. This residue resides in a Non_Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQT3.

Variant features alone are equivalent to phenotyping 0 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 (%)
-0.98 0.999 6.69 0.767 1 24

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
30059973 2018 1 1 0 0
Literature, cohort, and gnomAD 3 2 1 0
Variant features alone 15 14 1 0

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)
30059973 2018

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 V263I.
Neighbour residue Distance (Å) Observed variants
403 14
364 13
271 12 L271V,
266 6 L266H,
363 15
404 13 L404V, L404Q,
1544 13 T1544P,
270 11 Q270K,
1627 7
396 10 V396L, V396A,
1624 10 V1624I,
355 12 F355I, F355C,
1538 12
391 15
254 15
401 14 S401P,
1634 12 L1634P
1543 11 V1543L, V1543L, V1543A,
1542 7
361 11
260 6
366 13
365 9
258 9 V258A,
1546 9 M1546T,
369 12 M369K,
1545 10
1630 7 I1630V, I1630R,
1626 12 R1626C, R1626H, R1626P, R1626L,
267 6
1625 13
262 4 S262G,
357 15
256 11
399 11
272 14
397 14 I397V, I397F, I397T,
362 10
261 7
1628 8
1632 13 R1632C, R1632H, R1632L,
1539 11 C1539Y, C1539F,
392 11
255 13
269 11
395 10
393 14
1535 14
264 4
259 6
1633 11
1591 14 W1591X,
1548 15 E1548K, G1548K,
265 6 A265V,
358 10
263 0 V263I,
359 14 A359T, p.A359PfsX12,
1629 12 R1629G, R1629X, R1629Q,
1547 15 V1547L, V1547L,
1541 12
1540 14
1631 9 G1631D,
368 13
268 9 G268S,
257 10
400 11 G400R, G400R, G400E, G400A,
1623 12 c.4867delC, R1623X, R1623Q, R1623L,