SCN5A Variant A662S Detail

We estimate the penetrance of LQTS for SCN5A A662S around 1% and the Brugada syndrome penetrance around 13%. SCN5A A662S was found in a total of 6 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A662S is present in 6 alleles in gnomAD. A662S has been functionally characterized in 1 papers. This residue is located in a Mild_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 (2 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 A662S around 1% (0/16) and the Brugada syndrome penetrance around 13% (2/16).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-2.61 0.684 0.71 0.834 26 0
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
24631775 2014 1 0 0 1 SIDS
LITERATURE, COHORT, AND GNOMAD: - 6 6 0 0 -
VARIANT FEATURES ALONE: - 15 13 0 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.

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)
24631775 2014

A662S 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
647 15 A647S, A647V, A647D,
648 14 P648L,
649 14 C649Y, C649R,
650 13
651 13 D651H, c.1950_1953delAGAT,
652 12 G652S, G652D,
653 11
654 11 E654X , E654D, E654Q, E654K,
655 10 E655K,
656 9 P656L,
657 8
658 8 A658V,
659 7 R659W, R659Q,
660 5
661 4 R661Q, R661W,
662 0 A662S, c.1983_1993dupGGCCCTCAGCG,
663 4
664 5 S664G,
665 7 A665T, A665S,
666 8
667 8
668 9 V668I,
669 10
670 11
671 11 S671C,
672 12 A672T, A672S,
673 13 L673P, L673V,
674 13
675 14 c.2024_2025delAG,
676 14
677 15 E677V,