SCN5A Variant R1644L Detail

We estimate the penetrance of LQTS for SCN5A R1644L around 24% and the Brugada syndrome penetrance around 20%. SCN5A R1644L was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. R1644L is present in 1 alleles in gnomAD. R1644L 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 (2 diagnosed with Brugada syndrome) and 5 individuals for LQTS (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A R1644L around 24% (1/11) and the Brugada syndrome penetrance around 20% (2/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-6.41 0.99 -4.46 0.985 22 38
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 12 1 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.

R1644L 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
1643 7 I1643L,
1778 12
1653 15
1635 10
1652 12 M1652T, M1652R,
1634 8 L1634P,
1650 11 L1650F,
1641 6
1639 7 G1639A,
1779 13 T1779M,
1787 10 S1787N,
1654 15
1786 14 c.5356_5357delCT, L1786R, L1786Q,
1648 7
1649 10 A1649V,
1644 0 R1644L, R1644H, R1644C,
1640 7
256 12
1793 11 M1793K,
1781 14 E1781G, E1781D,
1789 6
1632 15 R1632L, R1632C, R1632H,
255 13
1645 5 T1645M,
1796 13
1788 10 c.5361_5364delTGAG,
1638 6 R1638X, R1638Q,
1651 9
259 14
1633 11
1791 13
1637 5
253 13
1792 10 D1792V, D1792Y, D1792N,
1636 9
407 15
1775 13 p.F1775LfsX15, F1775V,
1642 7 G1642E,
1790 10 D1790G, D1790N, p.D1790del,
1631 13 G1631D,
252 12
1647 6
1822 14 c.5464-5467delTCTG, c.5464_5467delTCTG,
1646 8
1782 12