SCN5A Variant L1840Q Detail

We estimate the penetrance of LQTS for SCN5A L1840Q around 26% and the Brugada syndrome penetrance around 9%. SCN5A L1840Q was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L1840Q is not present in gnomAD. L1840Q 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 L1840Q around 26% (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 0.961 1 32
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.

L1840Q 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 11 C1850S,
1855 9
1814 8
1794 14
1849 10 H1849R,
1856 7
1853 6 I1853V,
1834 10 S1834R,
1813 13
1818 12
1833 12 I1833M,
1880 13 M1880V,
1838 6
1832 11 Q1832E,
1811 8 Y1811X, Y1811N,
1843 11
1851 11 M1851V, M1851I,
1501 14 p.L1501_K1505del, L1501V,
1860 11 c.5577_5578dupAA,
1857 8
1812 13 S1812L, S1812X,
1858 12
1808 12
1835 7 L1835F,
1807 15 c.5420dupA,
1815 12
1821 15
1798 14 W1798X,
1854 10
1825 14 L1825P,
1848 6
1817 12
1846 11
1827 12
1839 5 D1839G,
1844 14
1859 11
1852 6 D1852V,
1816 15 D1816N, D1816E, c.5445_5446insT,
1842 7 M1842T, M1842V, M1842L,
1837 9
1831 12
1810 13
1836 8 I1836T,
1809 10 I1809M,
1841 5
1847 12 R1847H, R1847C,
1845 14 G1845R,
1840 0