SCN5A Variant C683S Detail

We estimate the penetrance of LQTS for SCN5A C683S around 24% and the Brugada syndrome penetrance around 26%. SCN5A C683S was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. C683S is present in 1 alleles in gnomAD. C683S 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 (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A C683S around 24% (1/11) and the Brugada syndrome penetrance around 26% (2/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-9.52 0.085 -1.33 0.89 33 29
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: - 1 1 0 0 -
VARIANT FEATURES ALONE: - 15 12 1 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.

C683S has 31 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
668 15 V668I,
669 14
670 14
671 13 S671C,
672 13 A672S, A672T,
673 12 L673V, L673P,
674 11
675 11 c.2024_2025delAG,
676 10
677 9 E677V,
678 8
679 8
680 7 R680H, R680C,
681 5 H681P,
682 4
683 0 C683G, C683R, C683S,
684 4
685 5
686 7 C686F,
687 8
688 8
689 9 R689C, R689H,
690 10
691 11 A691T, A691S,
692 11 Q692K,
693 12 R693C, R693H,
694 13 Y694C,
695 13
696 14 I696N,
697 14
698 15 E698X,