SCN5A Variant I727T Detail

We estimate the penetrance of LQTS for SCN5A I727T around 9% and the Brugada syndrome penetrance around 27%. SCN5A I727T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I727T is not present in gnomAD. I727T 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 I727T around 9% (0/10) and the Brugada syndrome penetrance around 27% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.962 34 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: - 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.

I727T has 53 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
719 12
723 6 I723V,
758 13 G758E,
811 12 c.2435_2436+3delTGGTAinsCGCCT, R811G, R811H,
733 10 F733L,
821 9
760 8 p.F760SfsX5,
721 10
812 11 L812Q,
1350 14 I1350T, I1350L,
759 10 p.I759FfsX6, c.2274delG, I759V,
792 14
764 13 M764K, M764R,
755 12
731 6 T731I,
819 11
726 5
818 6
825 14
781 13 W781X,
720 10
822 11 W822C, W822X,
749 15
788 11 I788V,
1346 13 L1346P, L1346I,
724 5 T724I,
762 14
728 5 V728I,
820 11
727 0
735 13 A735V, A735T, A735E,
732 9
734 10 M734V, c.2201dupT,
756 8
814 7 R814Q,
816 11 F816Y, F816L,
722 9
813 11 c.2436+12G>A, c.2437-5C>A,
757 11
817 7 K817E,
761 14
752 12 G752R,
815 7
1343 13
725 7
784 12 F784L,
763 12 E763D, E763K,
785 11 D785N,
730 6 N730K,
789 13 V789I, V789A,
753 12
1347 13
729 7 p.L729del,