SCN5A Variant I1848N Detail

We estimate the penetrance of LQTS for SCN5A I1848N around 18% and the Brugada syndrome penetrance around 17%. SCN5A I1848N was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1848N is not present in gnomAD. I1848N 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 (1 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 I1848N around 18% (0/10) and the Brugada syndrome penetrance around 17% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.934 15 21
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 0 1 - -
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.

I1848N has 51 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 7 C1850S,
1855 12
1814 7
1794 12
1849 6 H1849R,
1856 11
1806 11 p.Thr1806SerfsX27,
1853 6 I1853V,
1795 13 Y1795H, Y1795C, Y1795N, p.Y1795_E1796insD,
1834 14 S1834R,
1813 9
1818 12
1801 12
1838 11
1802 11
1832 13 Q1832E,
1811 7 Y1811N, Y1811X,
1843 7
1851 10 M1851V, M1851I,
1501 15 L1501V, p.L1501_K1505del,
1857 11
1812 10 S1812X, S1812L,
1808 6
1835 11 L1835F,
1804 15
1807 10 c.5420dupA,
1815 12
1821 15
1798 10 W1798X,
1854 11
1797 15 I1797V,
1848 0
1817 10
1846 8
1827 14
1839 10 D1839G,
1844 10
1852 6 D1852V,
1816 13 D1816N, D1816E, c.5445_5446insT,
1805 14
1842 6 M1842T, M1842V, M1842L,
1837 15
1831 14
1810 8
1836 13 I1836T,
1809 5 I1809M,
1506 14 P1506T, P1506S,
1841 6
1847 6 R1847H, R1847C,
1845 9 G1845R,
1840 6