SCN5A Variant I759V Detail

We estimate the penetrance of LQTS for SCN5A I759V around 14% and the Brugada syndrome penetrance around 19%. SCN5A I759V was found in a total of 2 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I759V is present in 2 alleles in gnomAD. I759V 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 (2 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 I759V around 14% (0/12) and the Brugada syndrome penetrance around 19% (2/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.92 0.001 2.33 0.719 36 27
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 13 0 2 - -
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.

I759V 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 11
723 8 I723V,
710 15
766 10
758 4 G758E,
811 14 c.2435_2436+3delTGGTAinsCGCCT, R811G, R811H,
733 13 F733L,
760 5 p.F760SfsX5,
721 13
765 10
759 0 c.2274delG, I759V, p.I759FfsX6,
792 12
764 9 M764K, M764R,
755 6
731 14 T731I,
754 10
726 7
720 12
750 14 Q750R,
788 12 I788V,
724 12 T724I,
793 12 L793F,
728 13 V728I,
713 14
762 6
727 10
767 12
756 6
814 11 R814Q,
722 9
757 6
768 15
786 14
817 13 K817E,
761 6
752 10 G752R,
790 15
725 11
763 6 E763K, E763D,
751 12 V751F, V751I,
796 14
785 12 D785N,
730 10 N730K,
789 10 V789I, V789A,
753 10
714 15 V714D, V714A,
729 11 p.L729del,