SCN5A Variant T724I Detail

We estimate the penetrance of LQTS for SCN5A T724I around 7% and the Brugada syndrome penetrance around 7%. SCN5A T724I was found in a total of 2 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T724I is present in 2 alleles in gnomAD. T724I 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 (0 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 T724I around 7% (0/12) and the Brugada syndrome penetrance around 7% (0/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-5.7 0.361 3.44 0.921 4 4
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: - 2 2 0 0 -
VARIANT FEATURES ALONE: - 15 15 0 0 - -
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.

T724I has 47 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
719 9
723 5 I723V,
733 14 F733L,
821 6
760 10 p.F760SfsX5,
721 6
759 12 c.2274delG, p.I759FfsX6, I759V,
764 13 M764R, M764K,
731 11 T731I,
819 10
726 6
826 14 N826D,
818 7
825 13
781 13 W781X,
720 7
822 9 W822X, W822C,
788 14 I788V,
724 0 T724I,
762 15
728 6 V728I,
820 9
713 15
823 13 P823T,
727 5
767 14
717 11 P717L,
732 12
734 15 c.2201dupT, M734V,
756 11
814 11 R814Q,
816 13 F816L, F816Y,
722 6
757 15
817 8 K817E,
716 13
815 11
1343 14
725 5
784 14 F784L,
763 12 E763K, E763D,
785 12 D785N,
730 10 N730K,
714 14 V714D, V714A,
729 9 p.L729del,
824 15
718 11 F718L,