SCN5A Variant H1923Q Detail

We estimate the penetrance of LQTS for SCN5A H1923Q around 2% and the Brugada syndrome penetrance around 23%. SCN5A H1923Q was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. H1923Q is not present in gnomAD. H1923Q 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 (2 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 H1923Q around 2% (0/10) and the Brugada syndrome penetrance around 23% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.501 30 0
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 13 0 2 - -
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.

H1923Q 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
1908 15 I1908V,
1909 14 Q1909R,
1910 14 R1910K,
1911 13
1912 13
1913 12 R1913H, R1913S, R1913C,
1914 11 R1914G,
1915 11 H1915P, H1915Y, H1915N, H1915Q,
1916 10
1917 9
1918 8
1919 8 R1919C, R1919H,
1920 7 S1920C,
1921 5
1922 4 K1922R, K1922N,
1923 0 H1923Y, H1923D,
1924 4 A1924T,
1925 5 S1925F, p.S1925CfsX20,
1926 7
1927 8 L1927P,
1928 8 F1928V,
1929 9 R1929H, R1929C,
1930 10 Q1930H,
1931 11
1932 11 A1932V,
1933 12 G1933V, G1933D, G1933A,
1934 13
1935 13 G1935S,
1936 14
1937 14 S1937A,
1938 15 E1938K, E1938X,