SCN5A Variant I832M Detail

We estimate the penetrance of LQTS for SCN5A I832M around 21% and the Brugada syndrome penetrance around 15%. SCN5A I832M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I832M is not present in gnomAD. I832M 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 (1 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 I832M around 21% (1/10) and the Brugada syndrome penetrance around 15% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.702 14 26
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 1 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.

I832M has 49 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
939 14 L939F,
937 10
839 8 L839P,
842 13
943 13 S943N,
1340 12 V1340I,
1457 13
1455 13
1461 11 T1461S,
1344 11 F1344S, F1344L,
819 12
836 7 V836M,
826 11 N826D,
825 10
934 12
781 14 W781X,
935 15 L935P,
1464 11 L1464P, c.4389_4396delCCTCTTTA,
944 13
830 8
833 4 G833R,
940 12 S940N,
1341 14
831 5
938 10
823 14 P823T,
840 11
942 8
843 13 T843A,
1456 10
1459 14 c.4376_4379delTCTT,
834 7 N834D,
827 9
1460 8 F1460L,
816 12 F816Y, F816L,
837 10
841 14 p.N841TfsX2, N841K,
1343 14
941 9 S941N, S941F,
1337 14
936 14
838 10
1467 15
824 12
829 5
832 0
835 5 S835L, S835A,
828 6 L828V,
1463 14 N1463Y,