SCN5A Variant G1639A Detail

We estimate the penetrance of LQTS for SCN5A G1639A around 7% and the Brugada syndrome penetrance around 9%. SCN5A G1639A was found in a total of 2 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. G1639A is present in 2 alleles in gnomAD. G1639A has been functionally characterized in 0 papers. This residue is located in a Non_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 G1639A around 7% (0/12) and the Brugada syndrome penetrance around 9% (1/12).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.7 0.967 0.39 0.59 8 5
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: - 2 2 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.

G1639A has 32 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
1643 9 I1643L,
1635 13
1634 12 L1634P,
1641 5
1639 0 G1639A,
1787 14 S1787N,
1648 14
1532 14 V1532F, V1532I,
1644 7 R1644L, R1644C, R1644H,
1640 3
256 14
1793 12 M1793K,
1789 10
255 13
1645 10 T1645M,
1796 15
251 14
1638 6 R1638X, R1638Q,
1633 12
1637 6
253 14
1792 14 D1792N, D1792V, D1792Y,
1636 9
1823 13 E1823K, p.E1823HfsX10,
1642 8 G1642E,
1528 14
1790 13 D1790G, D1790N, p.D1790del,
252 10
1647 12
1822 12 c.5464-5467delTCTG, c.5464_5467delTCTG,
1646 13
1782 14