SCN5A Variant T757I Detail

We estimate the penetrance of LQTS for SCN5A T757I around 15% and the Brugada syndrome penetrance around 36%. SCN5A T757I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T757I is not present in gnomAD. T757I has been functionally characterized in 0 papers. This residue is located in a 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 (3 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 T757I around 15% (0/10) and the Brugada syndrome penetrance around 36% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.897 50 16
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 12 0 3 - -
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.

T757I has 57 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
723 12 I723V,
766 14
758 4 G758E,
811 9 R811H, c.2435_2436+3delTGGTAinsCGCCT, R811G,
733 12 F733L,
808 13 R808P, R808C, R808H,
760 5 p.F760SfsX5,
765 12
812 14 L812Q,
759 6 p.I759FfsX6, c.2274delG, I759V,
792 6
764 11 M764K, M764R,
755 6
791 11 L791F,
731 13 T731I,
800 12 R800L, R800C, R800H,
754 6
726 10
797 12 G797V,
750 10 Q750R,
749 13
788 9 I788V,
724 15 T724I,
798 14
793 7 L793F,
728 14 V728I,
762 9
810 13
727 11
734 12 M734V, c.2201dupT,
756 6
814 8 R814Q,
807 13
722 14
813 13 c.2437-5C>A, c.2436+12G>A,
757 0
786 12
817 14 K817E,
761 6
752 8 G752R,
809 15
815 14
790 11
784 14 F784L,
763 11 E763D, E763K,
751 10 V751I, V751F,
796 8
785 12 D785N,
730 9 N730K,
789 7 V789I, V789A,
753 6
729 13 p.L729del,
795 9
748 15 M748I,
799 13
787 13
794 12