SCN5A Variant I891M Detail

We estimate the penetrance of LQTS for SCN5A I891M around 4% and the Brugada syndrome penetrance around 20%. SCN5A I891M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I891M is not present in gnomAD. I891M 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 I891M around 4% (0/10) and the Brugada syndrome penetrance around 20% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.79 23 1
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.

I891M has 77 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 0 I891T, I891N,
880 12
888 6
848 12 I848F,
223 14 V223L,
856 10 V856L,
890 5 I890T,
901 13 E901K, S901L,
919 7
862 14
896 9 C896S,
859 14
895 7 L895F,
894 5 I894M,
1455 15
1447 12
372 14
926 9
928 14 L928P,
925 11 I925F,
887 6
1451 12 V1451L, V1451D,
886 10 H886Q, H886P,
851 10 F851L, c.2552_2553dupGT, c.2550_2551dupGT, p.F851CfsX19,
897 10 G897R, G897E,
924 12 V924I,
927 11 N927S, N927K,
852 10
854 6 c.2559delT,
845 14 c.2533delG,
1422 13 M1422R,
857 9 G857D,
1418 14
902 9
882 15
892 6 F892I,
881 9
849 9
898 10
893 8 R893C, R893H,
921 11
922 6 V922I,
860 13 p.L860fsx89,
920 12
889 7
900 13
930 13 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 14 c.4376_4379delTCTT,
858 11 M858L,
918 9
855 10
1425 14
917 14 L917V, L917R,
865 14
1454 14
916 14
929 15
1448 15 I1448L, I1448T,
884 10
906 12
1421 13
885 12
847 10
846 10 L846R,
903 12 p.M903CfsX29,
853 6
877 15
879 11 W879R,
923 9
883 12
905 14
915 12 C915R,
899 11
850 6 V850M, c.2549_2550insTG,
914 14
861 11 p.F861WfsX90, c.2582_2583delTT,
931 13