SCN5A Variant G1406E Detail

We estimate the penetrance of LQTS for SCN5A G1406E around 2% and the Brugada syndrome penetrance around 65%. SCN5A G1406E was found in a total of 2 carriers in 1 papers and/or in gnomAD: 2 had Brugada syndrome, 0 had LQTS. G1406E is not present in gnomAD. G1406E has been functionally characterized in 2 papers. This residue is located in a Hotspot region for Brugada syndrome and a Non_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (5 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 G1406E around 2% (0/12) and the Brugada syndrome penetrance around 65% (7/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-6.52 1 -4.68 0.975 88 1
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
20129283 2010 2 0 2 0
LITERATURE, COHORT, AND GNOMAD: - 2 0 0 2 -
VARIANT FEATURES ALONE: - 15 10 0 5 - -
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)
20129283 2010
32533946 2020 HEK 33 -5.9 -2.5

G1406E has 60 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
1403 9
1746 12 A1746T, A1746V,
1357 12 A1357V,
1724 14
1352 11
1406 0 G1406R, G1406E,
1453 15
1351 14 M1351V, M1351R,
739 13
1745 13
1397 14 c.4189delT, c.4190delA,
1350 11 I1350T, I1350L,
1723 12 T1723N,
731 15 T731I,
1398 14 V1398M,
1411 8
1353 10 V1353M,
1407 3
737 12
1410 6
1714 15 D1714G,
1358 14 G1358R, G1358W,
1348 13 F1348L,
1404 5
1721 13
1349 8
1753 12 T1753A,
1346 10 L1346I, L1346P,
1341 15
1356 13 c.4066_4068delTT,
1412 9 L1412F,
1408 5 G1408R,
735 10 A735V, A735T, A735E,
732 14
1360 14 F1360C,
734 14 M734V, c.2201dupT,
1401 8
1399 13
1354 14
1424 14 I1424V,
1748 13 G1748D, p.G1748del,
738 11
1405 4 V1405M, V1405L,
740 15 p.N740del,
1409 6 Y1409X, Y1409C,
1400 10 V1400I,
1343 14
1345 11 W1345C,
1717 14 L1717P,
1342 11
1416 15 A1416G, c.4245+2T>A, c.4245+1G>C, c.4245+1G>A, A1416E,
736 11 L736P,
1750 13 L1750F,
1722 14 N1722D,
1749 10 I1749N,
1347 14
1415 14
1414 12 Q1414H,
1402 9
1413 10