SCN5A Variant T1754I Detail

We estimate the penetrance of LQTS for SCN5A T1754I around 18% and the Brugada syndrome penetrance around 12%. SCN5A T1754I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T1754I is not present in gnomAD. T1754I has been functionally characterized in 0 papers. This residue is located in a Non_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 T1754I around 18% (0/10) and the Brugada syndrome penetrance around 12% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.865 7 20
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
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.

T1754I 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
1746 12 A1746T, A1746V,
1417 14
1757 6
1413 12
1745 14
1756 6 I1756V,
1673 15
1675 12
1764 14 c.5290delG, V1764F,
1754 0
1707 11
1704 12 L1704H,
1410 13
1747 11 V1747M,
1716 15 p.L1716SfsX71,
1671 7
1762 11 I1762M, p.I1762del,
1668 13 M1668T,
1744 14 S1744I,
1721 15
1753 4 T1753A,
1672 13 S1672Y,
1334 13 I1334V,
1663 14
1759 9 S1759C,
1327 14
1709 15 T1709R, p.T1709del, T1709M,
1758 6 p.I1758del, I1758V,
1678 13 N1678S,
1755 6
1674 10 F1674V,
1713 11
1338 12 L1338V,
1748 9 p.G1748del, G1748D,
1708 12 T1708I,
1409 13 Y1409X, Y1409C,
1717 13 L1717P,
1342 15
1763 12 V1763L, V1763M,
1751 6
1308 14 L1308F,
1465 14 p.F1465_L1480dup,
1760 11
1750 6 L1750F,
1752 7
1670 11
1331 13 I1331V,
1761 10 L1761H, L1761F, c.5280delG,
1749 9 I1749N,
1710 13 S1710L,
1720 14 c.5157delC,
1679 14
1335 13 M1335R,
1667 10 V1667I,
1414 15 Q1414H,
1664 14
1666 15