SCN5A Variant I831T Detail

We estimate the penetrance of LQTS for SCN5A I831T around 26% and the Brugada syndrome penetrance around 16%. SCN5A I831T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I831T is not present in gnomAD. I831T 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 I831T around 26% (1/10) and the Brugada syndrome penetrance around 16% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.946 14 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 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.

I831T has 41 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 12 L939F,
937 10
839 11 L839P,
943 9 S943N,
1340 13 V1340I,
1461 13 T1461S,
1344 14 F1344S, F1344L,
819 13
836 10 V836M,
826 10 N826D,
825 10
934 13
1471 14
1464 11 L1464P, c.4389_4396delCCTCTTTA,
944 9
830 5
833 6 G833R,
940 10 S940N,
1468 14 V1468A, V1468F,
831 0
938 9
823 13 P823T,
840 14
942 6
1456 14
834 5 N834D,
827 6
1460 10 F1460L,
837 12
941 6 S941N, S941F,
1337 13
936 14
838 11
1467 13
1336 14
824 11
829 7
832 5
835 7 S835L, S835A,
828 6 L828V,
1463 15 N1463Y,