SCN5A Variant I1377N Detail

We estimate the penetrance of LQTS for SCN5A I1377N around 3% and the Brugada syndrome penetrance around 18%. SCN5A I1377N was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1377N is not present in gnomAD. I1377N 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 (1 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 I1377N around 3% (0/10) and the Brugada syndrome penetrance around 18% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.613 20 0
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 14 0 1 - -
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.

I1377N has 31 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
1362 15 R1362S, c.4083delG,
1363 14 C1363Y,
1364 14 I1364V,
1365 13 N1365S,
1366 13 Q1366R, Q1366H,
1367 12
1368 11
1369 11 G1369X, G1369R,
1370 10 D1370A, D1370G,
1371 9
1372 8
1373 8 L1373X, c.4118delT,
1374 7
1375 5 Y1375H,
1376 4
1377 0 I1377M,
1378 4 V1378M,
1379 5
1380 7 N1380K, p.N1380del,
1381 8
1382 8 S1382I,
1383 9 Q1383X,
1384 10 C1384Y,
1385 11
1386 11
1387 12 L1387F,
1388 13
1389 13
1390 14
1391 14 G1391R,
1392 15