SCN5A Variant L1657I Detail

We estimate the penetrance of LQTS for SCN5A L1657I around 20% and the Brugada syndrome penetrance around 33%. SCN5A L1657I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L1657I is not present in gnomAD. L1657I has been functionally characterized in 0 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 (3 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 L1657I around 20% (1/10) and the Brugada syndrome penetrance around 33% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.824 45 24
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 11 1 3 - -
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.

L1657I has 65 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 7
1659 7
404 13 L404V, L404Q,
1773 12
1765 12
396 15 V396A, V396L,
1653 5
1771 7 I1771T,
401 12 S401P,
1652 10 M1652R, M1652T,
1314 14 c.3940_3941delCT,
1320 10 M1320I,
1764 10 c.5290delG, V1764F,
1650 9 L1650F,
1656 4
1477 13 K1477N,
1762 14 p.I1762del, I1762M,
1470 14
1767 5 Y1767C,
1660 6 I1660S, I1660V,
1654 6
1648 14
1769 9
402 9 F402L,
1766 9 M1766V, M1766T, M1766L,
1319 10 G1319V,
1665 14
1649 11 A1649V,
1768 10 I1768V,
1774 10 c.5321_5324dupACTT, N1774D,
1473 11 F1473S, F1473C,
1663 11
399 9
397 13 I397F, I397T, I397V,
405 14
1657 0
1759 14 S1759C,
1662 10
1324 14
1317 13 F1317C,
1327 15
1318 13
1772 11 L1772V,
395 14
1323 10 V1323G,
394 13
410 15 A410V,
1770 6 I1770V,
1651 11
1708 15 T1708I,
1322 11 c.3963+4A>G, c.3963+2T>C,
407 13
1326 14 A1326S,
1763 10 V1763M, V1763L,
1775 14 p.F1775LfsX15, F1775V,
1661 7 G1661R, G1661E,
1655 6
1469 14 I1469V,
406 11 N406K, N406S,
398 8
1647 14
400 11 G400R, G400A, G400E,
1646 15
1664 10
1658 5