SCN5A Variant R568C Detail

We estimate the penetrance of LQTS for SCN5A R568C around 4% and the Brugada syndrome penetrance around 6%. SCN5A R568C was found in a total of 13 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. R568C is present in 13 alleles in gnomAD. R568C has been functionally characterized in 0 papers. This residue is located in a Non_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 (1 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 R568C around 4% (0/23) and the Brugada syndrome penetrance around 6% (1/23).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-5.83 0.99 0.33 0.683 7 7
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: - 13 13 0 0 -
VARIANT FEATURES ALONE: - 15 14 0 1 - -
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.

R568C 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
553 15 E553X, E553K,
554 14 S554I, S554N,
555 14 E555K,
556 13
557 13 H557Q, H557L, H557Y,
558 12 H558R,
559 11 T559I, T559R,
560 11
561 10
562 9
563 8 V563G,
564 8
565 7
566 5
567 4 L567Q,
568 0 R568C, R568H,
569 4 R569Q, R569W, c.1705dupC,
570 5 T570N,
571 7 S571I,
572 8 A572D, A572V, A572F, A572S,
573 8 Q573X, Q573R, Q573E,
574 9 c.1721delG, G574E,
575 10
576 11
577 11 S577N,
578 12 P578R, P578T,
579 13 G579R,
580 13
581 14 S581L,
582 14
583 15 P583L,