SCN5A Variant I788V Detail

We estimate the penetrance of LQTS for SCN5A I788V around 5% and the Brugada syndrome penetrance around 5%. SCN5A I788V was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I788V is present in 1 alleles in gnomAD. I788V has been functionally characterized in 0 papers. This residue is located in a Non_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 I788V around 5% (0/11) and the Brugada syndrome penetrance around 5% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.99 0.476 4.72 0.635 7 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: - 1 1 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.

I788V has 59 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,
758 11 G758E,
811 9 R811G, R811H, c.2435_2436+3delTGGTAinsCGCCT,
808 13 R808H, R808P, R808C,
760 8 p.F760SfsX5,
776 13 p.Y776del,
780 12
765 13
812 10 L812Q,
759 12 c.2274delG, p.I759FfsX6, I759V,
792 6
764 9 M764R, M764K,
755 15
777 13 F777L,
791 6 L791F,
731 14 T731I,
806 14 V806M,
754 14
819 14
726 13
818 12
781 11 W781X,
720 15
788 0 I788V,
724 14 T724I,
782 10 N782T,
793 9 L793F,
820 13
762 12
810 8
727 11
767 13
734 13 c.2201dupT, M734V,
756 12
814 5 R814Q,
807 11
816 10 F816L, F816Y,
813 6 c.2436+12G>A, c.2437-5C>A,
757 9
768 14
786 6
817 8 K817E,
761 9
779 15 Q779K, Q779X,
809 11
815 10
790 7
784 6 F784L,
763 12 E763K, E763D,
796 12
785 5 D785N,
783 10 I783T,
730 11 N730K,
789 5 V789A, V789I,
753 13
1347 15
795 11
787 5
794 10