SCN5A Variant I783M Detail

We estimate the penetrance of LQTS for SCN5A I783M around 5% and the Brugada syndrome penetrance around 21%. SCN5A I783M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I783M is not present in gnomAD. I783M has been functionally characterized in 0 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 I783M around 5% (0/10) and the Brugada syndrome penetrance around 21% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.799 25 2
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 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.

I783M has 34 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
773 11 P773S,
760 15 p.F760SfsX5,
780 4
776 7 p.Y776del,
765 14
792 15
764 10 M764K, M764R,
777 5 F777L,
791 12 L791F,
819 15
781 8 W781X,
788 10 I788V,
782 5 N782T,
820 13
774 13 Y774C, Y774D, c.2320delT, p.Y774TfsX28,
767 12
775 13
814 14 R814Q,
816 14 F816Y, F816L,
813 12 c.2436+12G>A, c.2437-5C>A,
768 11
786 6
817 12 K817E,
761 15
779 7 Q779K, Q779X,
778 9
790 10
784 6 F784L,
772 14 D772N,
771 13 L771V,
785 7 D785N,
783 0 I783T,
789 11 V789I, V789A,
787 6