SCN5A Variant N753I Detail

We estimate the penetrance of LQTS for SCN5A N753I around 12% and the Brugada syndrome penetrance around 28%. SCN5A N753I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. N753I is not present in gnomAD. N753I 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 (0 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A N753I around 12% (0/10) and the Brugada syndrome penetrance around 28% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.934 36 12
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.

N753I has 56 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 15 I723V,
758 9 G758E,
811 7 R811H, c.2435_2436+3delTGGTAinsCGCCT, R811G,
733 7 F733L,
741 14 p.M741_T742delinsI ,
808 9 R808P, R808C, R808H,
745 13
746 12 E746K,
760 10 p.F760SfsX5,
812 12 L812Q,
1350 13 I1350T, I1350L,
759 10 p.I759FfsX6, c.2274delG, I759V,
792 9
755 7
791 13 L791F,
731 11 T731I,
800 12 R800L, R800C, R800H,
754 5
726 11
1353 15 V1353M,
797 13 G797V,
737 11
750 5 Q750R,
749 6
788 13 I788V,
798 14
793 12 L793F,
728 13 V728I,
762 15
747 10 E747A,
810 13
727 12
735 12 A735V, A735T, A735E,
732 12
734 8 M734V, c.2201dupT,
756 6
814 9 R814Q,
807 13
813 14 c.2437-5C>A, c.2436+12G>A,
757 6
1354 13
761 12
752 4 G752R,
809 13
815 14
751 6 V751I, V751F,
796 9
736 12 L736P,
730 7 N730K,
789 13 V789I, V789A,
753 0
729 11 p.L729del,
795 9
748 9 M748I,
799 11
794 14