SCN5A Variant M1446K Detail

We estimate the penetrance of LQTS for SCN5A M1446K around 5% and the Brugada syndrome penetrance around 26%. SCN5A M1446K was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M1446K is not present in gnomAD. M1446K 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 (2 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 M1446K around 5% (0/10) and the Brugada syndrome penetrance around 26% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.976 32 2
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 13 0 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.

M1446K has 54 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
888 13
1355 8
1357 13 A1357V,
1430 11 D1430N,
1352 11
1426 13
1445 4 Y1445H,
1453 13
1447 6
1444 7 L1444I,
1351 11 M1351R, M1351V,
1440 14 W1440X,
1449 7 Y1449S, Y1449C,
1452 10
1429 7
1442 12 Y1442N, Y1442C,
806 12 V806M,
1450 8
1451 10 V1451L, V1451D,
1353 14 V1353M,
886 13 H886Q, H886P,
1358 15 G1358W, G1358R,
1433 12 G1433V, G1433R, G1433W,
1438 14 P1438L,
1348 13 F1348L,
1349 15
1431 10 S1431C,
1422 15 M1422R,
805 12 S805L,
892 15 F892I,
1359 11 K1359N, K1359M,
1434 13 c.4299+28C>T, c.4299delG, c.4300-1G>A, c.4299G>A, c.4299+1delG, c.4299+1G>T, c.4299_4300insG, c.4299+2T>A, Y1434X, c.4300-2A>T,
1356 8 c.4066_4068delTT,
1412 15 L1412F,
889 12
1360 13 F1360C,
1425 10
1454 14
1354 13
1427 12 A1427E, A1427S,
1446 0
1424 13 I1424V,
1432 12 R1432G, R1432S,
1448 6 I1448L, I1448T,
1439 15 Q1439R, Q1439H,
884 15
809 13
885 11
1443 6 N1443S,
1441 14 E1441Q,
1415 15
1428 8 A1428S, A1428V,
804 14
1402 13