SCN5A Variant V755A Detail

We estimate the penetrance of LQTS for SCN5A V755A around 14% and the Brugada syndrome penetrance around 30%. SCN5A V755A was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V755A is not present in gnomAD. V755A 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 (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 V755A around 14% (0/10) and the Brugada syndrome penetrance around 30% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.921 40 15
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.

V755A has 39 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 13 I723V,
758 6 G758E,
811 13 c.2435_2436+3delTGGTAinsCGCCT, R811G, R811H,
733 10 F733L,
760 9 p.F760SfsX5,
759 6 c.2274delG, p.I759FfsX6, I759V,
792 12
764 15 M764R, M764K,
755 0
731 14 T731I,
800 14 R800L, R800C, R800H,
754 5
726 9
750 9 Q750R,
749 11
788 15 I788V,
793 13 L793F,
728 14 V728I,
762 11
747 12 E747A,
727 12
732 14
734 14 M734V, c.2201dupT,
756 4
814 12 R814Q,
722 13
757 6
761 10
752 5 G752R,
725 14
763 12 E763D, E763K,
751 6 V751I, V751F,
796 12
730 10 N730K,
789 13 V789I, V789A,
753 7
729 11 p.L729del,
795 14
748 11 M748I,