SCN5A Variant A1656T Detail

We estimate the penetrance of LQTS for SCN5A A1656T around 31% and the Brugada syndrome penetrance around 28%. SCN5A A1656T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A1656T is not present in gnomAD. A1656T has been functionally characterized in 0 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 (2 diagnosed with Brugada syndrome) and 5 individuals for LQTS (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A A1656T around 31% (1/10) and the Brugada syndrome penetrance around 28% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.952 35 40
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 12 1 2 - -
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.

A1656T has 56 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
403 11
1659 5
1480 12 c.4438-1C>T, c.4437+5G>A,
1773 12
1765 14
1653 5
1315 13
1771 9 I1771T,
1652 9 M1652R, M1652T,
1314 12 c.3940_3941delCT,
1777 15 V1777L, V1777M,
1320 8 M1320I,
1764 13 V1764F, c.5290delG,
1650 11 L1650F,
1656 0
1477 11 K1477N,
1470 15
1767 8 Y1767C,
1660 6 I1660V, I1660S,
1654 6
1648 14
1769 10
402 13 F402L,
1766 10 M1766V, M1766L, M1766T,
1319 6 G1319V,
1649 11 A1649V,
1768 12 I1768V,
1774 9 c.5321_5324dupACTT, N1774D,
1473 10 F1473C, F1473S,
1663 11
399 13
1657 4
1474 15
1662 9
1324 12
1317 10 F1317C,
1327 14
1318 10
1772 13 L1772V,
1321 12 R1321K,
1323 8 V1323G,
1770 6 I1770V,
1651 11
1322 8 c.3963+4A>G, c.3963+2T>C,
1326 12 A1326S,
1763 12 V1763M, V1763L,
1476 12 Q1476X, Q1476R,
1775 15 p.F1775LfsX15, F1775V,
1661 9 G1661R, G1661E,
1655 4
1469 14 I1469V,
406 14 N406K, N406S,
1325 13 N1325S,
398 11
1664 12
1658 6