SCN5A Variant Q1483H Detail

We estimate the penetrance of LQTS for SCN5A Q1483H around 46% and the Brugada syndrome penetrance around 9%. SCN5A Q1483H was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Q1483H is present in 1 alleles in gnomAD. Q1483H has been functionally characterized in 0 papers. This residue is located in a Non_Hotspot region for Brugada syndrome and a Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (0 diagnosed with Brugada syndrome) and 5 individuals for LQTS (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A Q1483H around 46% (2/11) and the Brugada syndrome penetrance around 9% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-4.52 0.046 -1.69 0.739 4 75
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 2 0 - -
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.

Q1483H has 28 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
1480 11 c.4438-1C>T, c.4437+5G>A,
1486 6 F1486L, p.F1486del,
1485 5
1487 8 M1487K, M1487L,
1492 7
1875 14 M1875K, M1875T, p.M1875dup,
1477 12 K1477N,
1491 9 Q1491H,
1493 13 K1493R, K1493X, p.K1493del,
1478 7 K1478E,
1495 8 Y1495S,
1479 10
1496 11
1474 12
1481 7 G1481V, G1481E, G1481R,
1499 13
1488 10 T1488R,
1498 14 M1498T, M1498V, M1498R,
1876 15
1482 4
1476 13 Q1476X, Q1476R,
1484 5
1497 14
1490 13
1475 11 p.Q1475NfsX6, Q1475L,
1483 0 Q1483H,
1494 12
1489 10 E1489D,