SCN5A Variant N740I Detail

We estimate the penetrance of LQTS for SCN5A N740I around 5% and the Brugada syndrome penetrance around 54%. SCN5A N740I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. N740I is not present in gnomAD. N740I has been functionally characterized in 0 papers. This residue is located in a 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 (5 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 N740I around 5% (0/10) and the Brugada syndrome penetrance around 54% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.688 84 3
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 10 0 5 - -
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.

N740I has 35 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
1403 8
1357 10 A1357V,
742 7 T742A,
1724 13
741 6 p.M741_T742delinsI ,
745 10
1406 15 G1406R, G1406E,
1361 14
746 10 E746K,
739 4
1395 14
1397 12 c.4190delA, c.4189delT,
1723 15 T1723N,
1353 12 V1353M,
1407 14
737 10
1358 9 G1358W, G1358R,
1433 14 G1433V, G1433R, G1433W,
1404 10
749 13
743 10
1359 13 K1359N, K1359M,
1434 11 c.4299+28C>T, c.4299delG, c.4300-1G>A, c.4299G>A, c.4299+1delG, c.4299+1G>T, c.4299_4300insG, c.4299+2T>A, Y1434X, c.4300-2A>T,
735 14 A735E, A735T, A735V,
1435 12
1360 14 F1360C,
1401 13
1354 14
744 12
738 5
1405 14 V1405M, V1405L,
740 0 p.N740del,
736 10 L736P,
748 14 M748I,
1402 14