SCN5A Variant L1444I Detail

We estimate the penetrance of LQTS for SCN5A L1444I around 4% and the Brugada syndrome penetrance around 12%. SCN5A L1444I was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L1444I is present in 1 alleles in gnomAD. L1444I has been functionally characterized in 0 papers. This residue is located in a Mild_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 L1444I around 4% (0/11) and the Brugada syndrome penetrance around 12% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-1.01 0.886 1.55 0.522 12 1
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 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.

L1444I has 50 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
880 11
888 11
1355 14
890 13 I890T,
1430 9 D1430N,
1426 10
1445 6 Y1445H,
1447 6
1444 0 L1444I,
153 15
1440 9 W1440X,
149 14
1449 12 Y1449S, Y1449C,
1452 15
1429 6
1442 9 Y1442N, Y1442C,
1450 11
887 11
1451 12 V1451D, V1451L,
886 7 H886P, H886Q,
1433 15 G1433V, G1433R, G1433W,
1438 13 P1438L,
1423 15 D1423H,
876 14
1431 11 S1431C,
1422 13 M1422R,
882 13
892 13 F892I,
881 14
1359 14 K1359N, K1359M,
1356 13 c.4066_4068delTT,
889 9
1425 9
1427 11 A1427E, A1427S,
1446 7
1424 14 I1424V,
1432 12 R1432G, R1432S,
1448 9 I1448T, I1448L,
1439 12 Q1439H, Q1439R,
884 11
878 12 R878H, R878C, R878L,
1421 15
885 6
1443 6 N1443S,
1441 8 E1441Q,
152 13 D152N,
877 14
879 10 W879R,
883 9
1428 9 A1428V, A1428S,