SCN5A Variant I1809M Detail

We estimate the penetrance of LQTS for SCN5A I1809M around 22% and the Brugada syndrome penetrance around 7%. SCN5A I1809M was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1809M is present in 1 alleles in gnomAD. I1809M 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 (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 I1809M around 22% (1/11) and the Brugada syndrome penetrance around 7% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-2.01 0.8 3.39 0.62 9 29
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 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.

I1809M has 53 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 8 C1850S,
1803 11
1814 6
1794 11
1849 8 H1849R,
1856 14
1806 9 p.Thr1806SerfsX27,
1853 8 I1853V,
1795 12 p.Y1795_E1796insD, Y1795N, Y1795H, Y1795C,
1813 6
1818 11
1801 7
1838 14
1802 7
1832 14 Q1832E,
1820 13 A1820T, A1820V,
1811 8 Y1811N, Y1811X,
1843 10
1851 12 M1851V, M1851I,
1857 12
1507 15 p.Q1507_P1509del,
1812 8 S1812X, S1812L,
1509 15 P1509T,
1808 6
1835 12 L1835F,
1804 11
1819 14 D1819N,
1807 9 c.5420dupA,
1821 13
1815 10
1798 7 W1798X,
1854 12
1797 11 I1797V,
1800 12
1848 5
1817 8
1846 9
1827 14
1839 15 D1839G,
1799 12
1844 12
1852 10 D1852V,
1816 10 c.5445_5446insT, D1816E, D1816N,
1805 11
1842 10 M1842T, M1842V, M1842L,
1831 14
1810 5
1809 0 I1809M,
1506 12 P1506T, P1506S,
1841 11
1847 7 R1847C, R1847H,
1845 10 G1845R,
1840 10