SCN5A Variant G840A Detail

We estimate the penetrance of LQTS for SCN5A G840A around 26% and the Brugada syndrome penetrance around 25%. SCN5A G840A was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. G840A is not present in gnomAD. G840A 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 (2 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 G840A around 26% (1/10) and the Brugada syndrome penetrance around 25% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.907 30 33
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 12 1 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.

G840A has 52 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
848 11 I848F,
937 10
839 4 L839P,
842 6
240 13 V240M,
231 14 c.692_693delCA,
1455 11
1452 14
237 14
836 6 V836M,
234 8 P234S,
1451 15 V1451D, V1451L,
934 10
933 12
229 13
935 15 L935P,
845 8 c.2533delG,
232 12 V232I, V232F,
833 11 G833R,
940 14 S940N,
849 13
831 14
938 13
235 10 c.703+1G>A, G235R, c.704-1G>C,
840 0
942 15
843 4 T843A,
1456 12
930 12 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 13 c.4376_4379delTCTT,
834 12 N834D,
1460 12 F1460L,
837 5
239 9 I239V , I239V,
230 11 I230T, I230V, I230M,
242 15 A242D,
416 13 Y416C,
841 4 p.N841TfsX2, N841K,
236 11
847 10
941 13 S941N, S941F,
846 10 L846R,
936 14
238 11
233 8
838 5
844 5 L844RfsX3,
850 15 V850M, c.2549_2550insTG,
243 14
832 11
835 8 S835L, S835A,
931 14