SCN5A Variant M882I Detail

We estimate the penetrance of LQTS for SCN5A M882I around 3% and the Brugada syndrome penetrance around 48%. SCN5A M882I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M882I is not present in gnomAD. M882I has been functionally characterized in 0 papers. This residue is located in a 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 (4 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 M882I around 3% (0/10) and the Brugada syndrome penetrance around 48% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.651 73 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 11 0 4 - -
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.

M882I has 51 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
891 15 I891T, I891N,
880 5
888 14
154 11 P154L,
856 13 V856L,
890 12 I890T,
862 6
867 11 E867X, E867Q, E867K,
859 11
1444 13 L1444I,
153 12
1440 12 W1440X,
149 12
863 9
887 9
156 14 W156X, W156R,
864 10
886 8 H886Q, H886P,
909 13
854 12 c.2559delT,
876 8
857 10 G857D,
868 13 L868X, c.2602delC,
150 14
902 14
882 0
881 6
860 12 p.L860fsx89,
889 13
858 7 M858L,
855 12
865 7
148 14
884 10
906 13
866 7 S866L, S866P,
874 15 G874D,
910 14 S910L,
878 14 R878L, R878C, R878H,
885 11
1441 11 E1441Q,
152 8 D152N,
219 15 c.656_657insATTCA, R219H, p.R219HfsX11, R219C,
877 10
151 12
879 12 W879R,
869 11 R869S,
883 5
905 14
875 11
861 11 p.F861WfsX90, c.2582_2583delTT,