SCN5A Variant Q1918L Detail

We estimate the penetrance of LQTS for SCN5A Q1918L around 3% and the Brugada syndrome penetrance around 12%. SCN5A Q1918L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Q1918L is not present in gnomAD. Q1918L has been functionally characterized in 0 papers. This residue is located in a Non_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 (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 Q1918L around 3% (0/10) and the Brugada syndrome penetrance around 12% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.657 10 1
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.

Q1918L has 31 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
1903 15 V1903M,
1904 14 S1904L,
1905 14
1906 13 M1906V, M1906T,
1907 13
1908 12 I1908V,
1909 11 Q1909R,
1910 11 R1910K,
1911 10
1912 9
1913 8 R1913C, R1913S, R1913H,
1914 8 R1914G,
1915 7 H1915Q, H1915N, H1915P, H1915Y,
1916 5
1917 4
1918 0
1919 4 R1919C, R1919H,
1920 5 S1920C,
1921 7
1922 8 K1922R, K1922N,
1923 8 H1923Y, H1923D,
1924 9 A1924T,
1925 10 S1925F, p.S1925CfsX20,
1926 11
1927 11 L1927P,
1928 12 F1928V,
1929 13 R1929C, R1929H,
1930 13 Q1930H,
1931 14
1932 14 A1932V,
1933 15 G1933D, G1933A, G1933V,