SCN5A Variant Q1439H Detail

We estimate the penetrance of LQTS for SCN5A Q1439H around 2% and the Brugada syndrome penetrance around 20%. SCN5A Q1439H was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Q1439H is present in 1 alleles in gnomAD. Q1439H 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 Q1439H around 2% (0/11) and the Brugada syndrome penetrance around 20% (2/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-2.08 0.486 -1.25 0.571 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: - 1 1 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.

Q1439H has 44 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
1386 9
1430 6 D1430N,
1426 10
1445 14 Y1445H,
1361 11
1444 12 L1444I,
1440 7 W1440X,
1382 7 S1382I,
1395 13
1380 9 N1380K, p.N1380del,
1429 9
1442 5 Y1442N, Y1442C,
1358 15 G1358W, G1358R,
1362 9 R1362S, c.4083delG,
1433 10 G1433V, G1433R, G1433W,
1438 5 P1438L,
1388 12
1387 8 L1387F,
1437 6
876 15
1384 10 C1384Y,
1431 8 S1431C,
1383 7 Q1383X,
1359 12 K1359N, K1359M,
1434 14 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,
1356 15 c.4066_4068delTT,
1381 11
1435 14
1360 13 F1360C,
1425 15
1427 10 A1427E, A1427S,
1385 13
1446 15
1432 6 R1432G, R1432S,
1389 15
1439 0 Q1439R, Q1439H,
1364 13 I1364V,
878 13 R878L, R878C, R878H,
1443 9 N1443S,
1441 7 E1441Q,
1379 14
1428 11 A1428S, A1428V,
1363 11 C1363Y,
1436 9