SCN5A Variant V1340L Detail

We estimate the penetrance of LQTS for SCN5A V1340L around 12% and the Brugada syndrome penetrance around 19%. SCN5A V1340L was found in a total of 0 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V1340L is not present in gnomAD. V1340L has been functionally characterized in 1 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (1 diagnosed with Brugada syndrome) and 5 individuals for LQTS (0 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A V1340L around 12% (0/10) and the Brugada syndrome penetrance around 19% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 15 12
PROVEAN scores less than -2 are considered deleterious. REVEL scores higher than 0.5 or 0.75 are considered likely pathogenic (higher sensitivity with the former cutoff, higher specificity with the latter cutoff). A PolyPhen-2 score of 0.85 or greater is considered likely pathogenic. BLAST-PSSM reflects the evolutionary conservation of residue substitutions, more negative numbers indicate fewer observations of the specific substitution than is expected. Penetrance Density is our previously published method to calculate the average BrS/LQTS probability density in a shell of residues surrounding a residue of interest (Kroncke et al. 2019).

Reported Carrier Data

PubMed ID Year Carriers Unaffected LQT3 BrS1 Other Other Disease
29781517 2018 5 0 0 2 Atrial standstill
LITERATURE, COHORT, AND GNOMAD: - 0 0 0 0 -
VARIANT FEATURES ALONE: - 15 14 0 1 - -
Summary totals might not agree with the literature table because of duplicate patients, which were excluded from the total counts. We do not distinguish here between multiple missense codons. Missense variants are combined across degenerate codon substitutions since codon-level data were not consistently available for curation.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
29781517 2018 HEK 47 12.5 0.23

V1340L has 57 previously observed neighbors within 15 angstroms

A residue within a folded protein on average has nearest neighbors that fall roughly into two shells: a "nearest" neighbor around 5-6 angstroms and a second shell around 11 angstroms. All variants shown in the rightmost column have been observed in at least one individual in the literature or gnomAD.

Neighbor Distance (Angstroms) Variants Observed in Individuals
821 13
1340 0 V1340I,
1457 10
1453 13
1455 15
1757 14
1339 5 L1339F, p.L1339del,
1461 7 T1461S,
1333 11
1344 5 F1344L, F1344S,
819 10
826 11 N826D,
818 11
825 7
1458 13 S1458Y,
1348 12 F1348L,
1464 9 c.4389_4396delCCTCTTTA, L1464P,
1349 14
822 9 W822C, W822X,
944 15
830 15
1346 10 L1346P, L1346I,
1341 4
1334 10 I1334V,
1468 13 V1468F, V1468A,
831 13
1462 11
938 14
1412 15 L1412F,
823 11 P823T,
942 12
1456 11
827 11
1460 9 F1460L,
816 11 F816L, F816Y,
1338 7 L1338V,
1409 13 Y1409C, Y1409X,
815 12
1343 5
1345 8 W1345C,
1337 5
1342 7
1416 15 c.4245+1G>A, A1416E, A1416G, c.4245+2T>A, c.4245+1G>C,
1332 14 P1332Q, P1332L,
1465 10 p.F1465_L1480dup,
1467 14
1331 15 I1331V,
1761 14 L1761F, L1761H, c.5280delG,
1347 11
1336 7
824 7
829 10
1335 10 M1335R,
832 12
828 7 L828V,
1463 13 N1463Y,
1413 14