SCN5A Variant H738Q Detail

We estimate the penetrance of LQTS for SCN5A H738Q around 16% and the Brugada syndrome penetrance around 42%. SCN5A H738Q was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. H738Q is not present in gnomAD. H738Q has been functionally characterized in 0 papers. This residue is located in a Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (4 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 H738Q around 16% (0/10) and the Brugada syndrome penetrance around 42% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.798 61 19
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 11 0 4 - -
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.

H738Q has 45 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
1355 14
1403 6
1357 8 A1357V,
742 8 T742A,
733 13 F733L,
1724 13
741 6 p.M741_T742delinsI ,
808 15 R808C, R808P, R808H,
745 9
1352 12
1406 11 G1406E, G1406R,
1361 15
746 11 E746K,
739 5
1397 12 c.4189delT, c.4190delA,
1350 12 I1350T, I1350L,
1723 14 T1723N,
1398 15 V1398M,
1353 8 V1353M,
1407 10
737 7
1358 9 G1358W, G1358R,
1404 6
1349 13
749 11
743 12
1359 13 K1359N, K1359M,
1356 13 c.4066_4068delTT,
1434 12 c.4300-2A>T, Y1434X, c.4299G>A, c.4299+2T>A, c.4299+1G>T, c.4300-1G>A, c.4299+1delG, c.4299_4300insG, c.4299+28C>T, c.4299delG,
1408 12 G1408R,
735 10 A735V, A735T, A735E,
1435 15
732 14
1360 13 F1360C,
734 13 M734V, c.2201dupT,
1401 11
1354 11
744 13
738 0
1405 9 V1405L, V1405M,
740 5 p.N740del,
1400 15 V1400I,
736 6 L736P,
748 13 M748I,
1402 11