SCN5A Variant M1838I Detail

We estimate the penetrance of LQTS for SCN5A M1838I around 28% and the Brugada syndrome penetrance around 9%. SCN5A M1838I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1838I is not present in gnomAD. M1838I 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 (0 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 M1838I around 28% (1/10) 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 0.95 1 36
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 1 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.

M1838I has 48 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 9
1814 10
1794 15
1849 14 H1849R,
1856 5
1853 9 I1853V,
1828 13 A1828S, A1828T,
1834 6 S1834R,
1818 11
1833 10 I1833M,
1880 13 M1880V,
1866 15
1824 14 P1824A,
1838 0
1832 10 Q1832E,
1811 12 Y1811X, Y1811N,
1863 11
1851 14 M1851V, M1851I,
1501 15 L1501V, p.L1501_K1505del,
1860 7 c.5577_5578dupAA,
1857 7
1862 12
1858 10
1835 5 L1835F,
1819 15 D1819N,
1861 11 V1861I, V1861F,
1864 12
1815 12
1821 14
1826 15 R1826H, R1826C,
1854 12
1825 12 L1825P,
1848 11
1817 13
1877 13 E1877K,
1827 9
1839 6 D1839G,
1859 8
1852 10 D1852V,
1842 13 M1842L, M1842V, M1842T,
1837 5
1831 10
1836 7 I1836T,
1809 14 I1809M,
1841 10
1830 14
1840 6