SCN5A Variant I894M Detail

We estimate the penetrance of LQTS for SCN5A I894M around 6% and the Brugada syndrome penetrance around 19%. SCN5A I894M was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I894M is present in 1 alleles in gnomAD. I894M 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 (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 I894M around 6% (0/11) and the Brugada syndrome penetrance around 19% (2/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-2.25 0.998 1.13 0.777 28 5
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: - 1 1 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.

I894M has 74 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 5 I891T, I891N,
880 14
888 10
856 14 V856L,
890 7 I890T,
901 10 E901K, S901L,
919 6
363 14
896 7 C896S,
895 5 L895F,
894 0 I894M,
372 9
926 9
371 14 Q371E,
928 11 L928P,
925 11 I925F,
904 13 W904X,
366 13
887 10
1451 14 V1451L, V1451D,
886 13 H886P, H886Q,
1458 14 S1458Y,
851 14 c.2552_2553dupGT, p.F851CfsX19, F851L, c.2550_2551dupGT,
897 5 G897R, G897E,
924 10 V924I,
927 8 N927S, N927K,
852 14
854 11 c.2559delT,
1422 12 M1422R,
857 12 G857D,
1418 11
902 7
892 7 F892I,
373 12
881 12
849 12
898 6
893 5 R893C, R893H,
921 10
922 6 V922I,
920 9
889 10
900 9
930 13 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 13 c.4376_4379delTCTT,
918 10
855 15
1425 14
917 13 L917V, L917R,
1454 13
916 12
929 13
884 15
906 12
878 15 R878H, R878L, R878C,
1421 11
847 14
846 12 L846R,
903 9 p.M903CfsX29,
367 12 R367C, R367H, R367L,
853 9
370 11 T370M,
879 11 W879R,
923 6
905 13
915 12 C915R,
899 6
850 9 V850M, c.2549_2550insTG,
914 15
932 15
861 14 p.F861WfsX90, c.2582_2583delTT,
1419 14 K1419E,
907 14
931 11