SCN5A Variant G874D Detail

We estimate the penetrance of LQTS for SCN5A G874D around 5% and the Brugada syndrome penetrance around 11%. SCN5A G874D was found in a total of 2 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. G874D is present in 2 alleles in gnomAD. G874D 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 (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 G874D around 5% (0/12) and the Brugada syndrome penetrance around 11% (1/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-1.11 0.003 -0.13 0.663 12 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: - 2 2 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.

G874D has 24 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
880 12
870 6
867 14 E867Q, E867X, E867K,
1440 13 W1440X,
864 14
871 5
909 12
876 7
868 10 L868X, c.2602delC,
882 15
872 6 D872N,
865 11
866 12 S866L, S866P,
874 0 G874D,
878 12 R878H, R878L, R878C,
350 14 H350Q,
1441 15 E1441Q,
877 8
879 15 W879R,
869 8 R869S,
905 12
875 4
908 11
873 4 S873A,