SCN5A Variant V1323G Detail

We estimate the penetrance of LQTS for SCN5A V1323G around 14% and the Brugada syndrome penetrance around 53%. SCN5A V1323G was found in a total of 1 carriers in 1 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. V1323G is not present in gnomAD. V1323G has been functionally characterized in 1 papers. This residue is located in a 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 (4 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 V1323G around 14% (0/11) and the Brugada syndrome penetrance around 53% (5/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-6.76 0.993 -6.21 0.97 69 23
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 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
VARIANT FEATURES ALONE: - 15 11 0 4 - -
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

V1323G has 67 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
1328 9 V1328M,
1659 7
1271 14 W1271C,
1480 11 c.4438-1C>T, c.4437+5G>A,
1773 13
1765 12
1653 12
1472 11 p.N1472del, N1472S,
1315 8
1771 13 I1771T,
1314 9 c.3940_3941delCT,
1320 4 M1320I,
1764 12 V1764F, c.5290delG,
1666 13
1656 8
1477 10 K1477N,
1471 15
1762 11 I1762M, p.I1762del,
1470 13
1466 15 c.4396_4397insG,
1767 10 Y1767C,
1313 13
1660 6 I1660S, I1660V,
1654 14
1329 10 G1329S,
1310 15
1769 10
1316 13 R1316Q, R1316L,
1766 7 M1766T, M1766V, M1766L,
1319 6 G1319V,
1665 15
1768 13 I1768V,
1774 14 N1774D, c.5321_5324dupACTT,
1479 12
1473 7 F1473C, F1473S,
1334 15 I1334V,
1468 14 V1468A, V1468F,
1663 8
1657 10
1474 13
1759 13 S1759C,
1662 10
1324 4
1317 10 F1317C,
1327 7
1758 13 I1758V, p.I1758del,
1318 10
1330 11 A1330T, A1330P, A1330D,
1772 15 L1772V,
1321 9 R1321K,
1323 0 V1323G,
1770 9 I1770V,
1322 4 c.3963+4A>G, c.3963+2T>C,
1312 12
1326 6 A1326S,
1763 9 V1763M, V1763L,
1311 12 L1311P,
1476 8 Q1476X, Q1476R,
1661 10 G1661R, G1661E,
1331 13 I1331V,
1655 11
1475 13 p.Q1475NfsX6, Q1475L,
1469 11 I1469V,
1325 6 N1325S,
1667 13 V1667I,
1664 11
1658 12