SCN5A Variant L1647I Detail

We estimate the penetrance of LQTS for SCN5A L1647I around 26% and the Brugada syndrome penetrance around 25%. SCN5A L1647I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L1647I is not present in gnomAD. L1647I 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 L1647I around 26% (1/10) and the Brugada syndrome penetrance around 25% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.897 30 33
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 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.

L1647I has 65 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
403 10
1643 5 I1643L,
404 11 L404V, L404Q,
1778 11
1653 10
1635 12
254 13
1771 11 I1771T,
1652 10 M1652T, M1652R,
1634 7 L1634P,
1777 14 V1777L, V1777M,
250 14
1650 5 L1650F,
260 11
1641 10
258 14 V258A,
1639 12 G1639A,
1779 13 T1779M,
1776 14
1787 13 S1787N,
1654 10
1648 7
1630 14 I1630R, I1630V,
1649 6 A1649V,
1774 12 N1774D, c.5321_5324dupACTT,
1644 6 R1644L, R1644H, R1644C,
1640 10
256 8
399 13
405 15
1657 14
1781 15 E1781G, E1781D,
1789 11
1632 15 R1632L, R1632C, R1632H,
255 11
1772 14 L1772V,
1645 6 T1645M,
251 14
410 13 A410V,
1788 12 c.5361_5364delTGAG,
1770 15 I1770V,
1638 11 R1638X, R1638Q,
1651 6
259 11
1633 11
1591 14 W1591X,
1637 8
408 14
253 10
1792 14 D1792V, D1792Y, D1792N,
1636 12
407 9
1775 10 p.F1775LfsX15, F1775V,
1642 8 G1642E,
1655 14
1790 15 D1790G, D1790N, p.D1790del,
1631 11 G1631D,
406 14 N406S, N406K,
252 11
411 13 V411M,
1647 0
257 12
400 13 G400E, G400R, G400A,
1646 4
1782 14