SCN5A Variant M1851I Detail

We estimate the penetrance of LQTS for SCN5A M1851I around 4% and the Brugada syndrome penetrance around 8%. SCN5A M1851I was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1851I is present in 1 alleles in gnomAD. M1851I has been functionally characterized in 0 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a Non_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 (0 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A M1851I around 4% (0/11) and the Brugada syndrome penetrance around 8% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.53 0.525 -1.09 0.519 10 7
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: - 1 1 0 0 -
VARIANT FEATURES ALONE: - 15 15 0 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.

M1851I has 47 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 4 C1850S,
1855 8
1814 14
1794 10
1849 5 H1849R,
1856 10
1806 12 p.Thr1806SerfsX27,
1853 7 I1853V,
1795 9 p.Y1795_E1796insD, Y1795N, Y1795H, Y1795C,
1880 14 M1880V,
1838 14
1802 14
1504 9 K1504E,
1843 13
1851 0 M1851V, M1851I,
1501 7 p.L1501_K1505del, L1501V,
1857 11
1507 14 p.Q1507_P1509del,
1505 9 p.K1505_Q1507del, K1505N,
1858 11
1808 10
1786 15 L1786Q, L1786R, c.5356_5357delCT,
1807 8 c.5420dupA,
1798 10 W1798X,
1854 5
1825 14 L1825P,
1848 10
1499 12
1817 14
1498 10 M1498T, M1498V, M1498R,
1839 12 D1839G,
1500 12 p.K1500del,
1859 13
1876 15
1791 11
1852 5 D1852V,
1792 14 D1792Y, D1792V, D1792N,
1502 7 G1502A, G1502S,
1805 13
1842 14 M1842T, M1842V, M1842L,
1497 12
1809 12 I1809M,
1506 10 P1506T, P1506S,
1841 11
1503 9 S1503Y,
1847 14 R1847C, R1847H,
1840 11