SCN5A Variant M1498I Detail

We estimate the penetrance of LQTS for SCN5A M1498I around 49% and the Brugada syndrome penetrance around 9%. SCN5A M1498I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1498I is not present in gnomAD. M1498I has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (0 diagnosed with Brugada syndrome) and 5 individuals for LQTS (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A M1498I around 49% (2/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.929 2 66
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 13 2 0 - -
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.

M1498I has 49 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
1850 14 C1850S,
1855 7
1785 11
1794 14
1856 11
1853 14 I1853V,
1879 12
1486 15 p.F1486del, F1486L,
1880 12 M1880V,
1492 10
1504 11 K1504E,
1875 13 M1875K, M1875T, p.M1875dup,
1491 10 Q1491H,
1863 15
1851 10 M1851V, M1851I,
1501 5 L1501V, p.L1501_K1505del,
1857 13
1874 12
1862 10
1493 11 K1493X, K1493R, p.K1493del,
1858 8
1787 13 S1787N,
1786 11 c.5356_5357delCT, L1786Q, L1786R,
1861 12 V1861F, V1861I,
1495 6 Y1495S,
1496 7
1854 9
1481 14 G1481V, G1481R, G1481E,
1825 14 L1825P,
1781 12 E1781G, E1781D,
1499 6
1877 12 E1877K,
1784 13 E1784K, E1784X,
1498 0 M1498T, M1498R, M1498V,
1839 14 D1839G,
1788 13 c.5361_5364delTGAG,
1500 7 p.K1500del,
1859 10
1876 8
1791 11
1482 14
1852 13 D1852V,
1502 7 G1502A, G1502S,
1497 4
1490 14
1790 14 D1790G, D1790N, p.D1790del,
1483 14 Q1483H,
1494 5
1503 10 S1503Y,