SCN5A Variant L399M

Summary of observed carriers, functional annotations, and structural context for SCN5A L399M. Data combine curated literature, international cohorts, and gnomAD observations.

Estimated LQT3 penetrance

22%

1/10 effective observations

Estimated BrS1 penetrance

20%

2/10 effective observations

Total carriers

0

0 BrS1 · 0 LQT3 · 0 unaffected

L399M has not been reported in gnomAD. This residue resides in a Mild_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 0.772 23 27

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
Literature, cohort, and gnomAD 0 0 0 0
Variant features alone 15 12 1 2

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

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 L399M.
Neighbour residue Distance (Å) Observed variants
403 6
1659 14
404 9 L404V, L404Q,
396 7 V396L, V396A,
1624 15 V1624I,
1653 12
391 11
1771 12 I1771T
401 8 S401P,
1634 14 L1634P,
1764 14 c.5290delG, V1764F,
371 13 Q371E,
1650 10 L1650F,
260 9
366 15
1656 13
365 12
369 10 M369K,
1767 10 Y1767C,
1660 12 I1660V, I1660S,
1654 9
402 7 F402L, F402L, F402L,
1630 15 I1630V, I1630R,
1649 14 A1649V,
1768 14 I1768V,
267 13
262 14 S262G,
256 13
399 0
397 7 I397V, I397F, I397T,
405 12
1657 9
261 12
1662 14
1709 14 p.T1709del, T1709R, T1709M,
1628 13
392 10
395 5
393 11
390 13
394 8
1770 14 I1770V,
264 9
1651 12
1708 15 T1708I,
259 13
265 14 A265V,
374 14 W374G,
1705 14
407 13
263 11 V263I,
370 14 T370M,
1661 11 G1661R, G1661R, G1661E,
1655 12
1631 13 G1631D,
406 12 N406S, N406K, N406K,
368 11
398 5
1647 13
257 13
400 5 G400R, G400R, G400E, G400A,
1646 15
1664 13
1658 9