SCN5A Variant K820N Detail

We estimate the penetrance of LQTS for SCN5A K820N around 10% and the Brugada syndrome penetrance around 33%. SCN5A K820N was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. K820N is not present in gnomAD. K820N has been functionally characterized in 0 papers. This residue is located in a 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 (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 K820N around 10% (0/10) and the Brugada syndrome penetrance around 33% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.691 47 10
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.

K820N 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 13
723 10 I723V,
821 5
760 14 p.F760SfsX5,
780 10
776 14 p.Y776del,
721 12
764 13 M764K, M764R,
819 5
726 14
826 7 N826D,
818 8
825 9
781 5 W781X,
720 9
822 9 W822C, W822X,
830 12
788 13 I788V,
724 9 T724I,
782 10 N782T,
728 14 V728I,
820 0
823 8 P823T,
727 11
767 13
717 14 P717L,
827 12
814 14 R814Q,
816 10 F816Y, F816L,
722 14
813 14 c.2437-5C>A, c.2436+12G>A,
786 14
817 6 K817E,
779 10 Q779K, Q779X,
716 14
815 12
1343 15
725 14
784 9 F784L,
763 14 E763K, E763D,
785 10 D785N,
783 13 I783T,
714 13 V714A, V714D,
824 11
829 11
787 15
828 13 L828V,