SCN5A Variant K817M Detail

We estimate the penetrance of LQTS for SCN5A K817M around 10% and the Brugada syndrome penetrance around 42%. SCN5A K817M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. K817M is not present in gnomAD. K817M 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 (4 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 K817M around 10% (0/10) and the Brugada syndrome penetrance around 42% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.95 60 9
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 11 0 4 - -
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.

K817M has 61 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 12
723 8 I723V,
758 15 G758E,
811 14 c.2435_2436+3delTGGTAinsCGCCT, R811G, R811H,
821 7
760 9 p.F760SfsX5,
780 11
776 13 p.Y776del,
721 12
812 12 L812Q,
759 13 p.I759FfsX6, c.2274delG, I759V,
792 14
764 10 M764K, M764R,
791 14 L791F,
1344 14 F1344S, F1344L,
731 11 T731I,
819 6
726 10
826 11 N826D,
818 5
825 11
781 6 W781X,
720 9
822 10 W822C, W822X,
788 8 I788V,
724 8 T724I,
782 10 N782T,
762 14
728 11 V728I,
820 6
810 14
823 12 P823T,
727 7
767 12
734 14 M734V, c.2201dupT,
756 13
814 8 R814Q,
816 7 F816Y, F816L,
722 12
813 9 c.2436+12G>A, c.2437-5C>A,
757 14
786 11
817 0 K817E,
761 14
779 13 Q779K, Q779X,
815 7
790 15
1343 13
725 12
784 7 F784L,
763 12 E763D, E763K,
785 6 D785N,
783 12 I783T,
730 11 N730K,
789 12 V789I, V789A,
1347 13
714 14 V714D, V714A,
729 13 p.L729del,
824 14
829 12
787 11