SCN5A Variant I1637T Detail

We estimate the penetrance of LQTS for SCN5A I1637T around 15% and the Brugada syndrome penetrance around 18%. SCN5A I1637T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1637T is not present in gnomAD. I1637T has been functionally characterized in 0 papers. This residue is located in a Mild_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 (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 I1637T around 15% (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 0.971 17 16
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.

I1637T 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
1643 6 I1643L,
1531 14
1635 8
1634 6 L1634P,
1650 13 L1650F,
260 13
1641 8
258 15 V258A,
1639 6 G1639A,
1787 14 S1787N,
1648 11
1630 12 I1630R, I1630V,
1532 13 V1532I, V1532F,
1649 13 A1649V,
1644 5 R1644H, R1644C, R1644L,
1640 6
256 10
1793 13 M1793K,
1789 10
1632 12 R1632L, R1632C, R1632H,
1539 14 C1539Y, C1539F,
255 11
1645 9 T1645M,
1796 14
1535 12
251 14
1788 14 c.5361_5364delTGAG,
1638 6 R1638Q, R1638X,
1651 12
259 11
1633 7
1591 14 W1591X,
1637 0
253 13
1792 13 D1792Y, D1792N, D1792V,
1636 5
1642 9 G1642E,
1528 15
1790 14 p.D1790del, D1790N, D1790G,
1631 10 G1631D,
252 10
1647 8
257 14
1646 10