SCN5A Variant W822C Detail

We estimate the penetrance of LQTS for SCN5A W822C around 12% and the Brugada syndrome penetrance around 56%. SCN5A W822C was found in a total of 1 carriers in 2 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. W822C is not present in gnomAD. W822C has been functionally characterized in 2 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 (5 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 W822C around 12% (0/11) and the Brugada syndrome penetrance around 56% (6/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-12.87 0.999 -4.11 0.948 72 3
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
22840528 2012 1 0 1 0
24721456 2014 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
VARIANT FEATURES ALONE: - 15 10 0 5 - -
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.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
22840528 2012
24721456 2014

W822C 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,
821 5
1340 9 V1340I,
1339 7 p.L1339del, L1339F,
721 12
1344 12 F1344S, F1344L,
731 13 T731I,
819 6
826 8 N826D,
726 15
818 6
825 6
781 13 W781X,
720 13
822 0 W822X, W822C,
830 15
1346 13 L1346I, L1346P,
724 9 T724I,
1341 13
728 11 V728I,
820 9
823 6 P823T,
727 11
827 11
816 12 F816Y, F816L,
1338 13 L1338V,
817 10 K817E,
815 11
1343 9
1337 13
1342 12
725 13
1347 14
729 15 p.L729del,
1336 10
824 6
829 12
1335 13 M1335R,
828 11 L828V,