SCN5A Variant N1734I Detail

We estimate the penetrance of LQTS for SCN5A N1734I around 5% and the Brugada syndrome penetrance around 20%. SCN5A N1734I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. N1734I is not present in gnomAD. N1734I 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 N1734I around 5% (0/10) and the Brugada syndrome penetrance around 20% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.744 23 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.

N1734I has 26 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
1739 12 R1739Q, R1739W,
1734 0
1298 9 P1298L,
1737 9 G1737D,
1741 13 D1741E, D1741Y, D1741N,
1731 9
1678 15 N1678S,
1297 10
1729 13 D1729N,
1300 11
1740 9 G1740R,
1735 5
1296 9 M1296T,
1733 4
1742 11
1299 13 c.3894delC,
1732 5
1736 9
1293 12 F1293S,
1743 14 G1743R, G1743E,
1730 10 P1730H, P1730L, P1730A,
1738 7 S1738T, S1738F,
1294 14 A1294G,
1680 14 A1680T, A1680P,
1295 14 E1295K,
1681 14 c.5040_5042delTTAinsC, Y1681F,