SCN5A Variant I1454T Detail

We estimate the penetrance of LQTS for SCN5A I1454T around 15% and the Brugada syndrome penetrance around 35%. SCN5A I1454T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1454T is not present in gnomAD. I1454T has been functionally characterized in 0 papers. This residue is located in a 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 (3 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 I1454T around 15% (0/10) and the Brugada syndrome penetrance around 35% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.941 48 17
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 0 3 - -
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.

I1454T has 68 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
891 14 I891T, I891N,
888 12
890 15 I890T,
896 8 C896S,
895 10 L895F,
1417 10
839 14 L839P,
1352 15
842 15
894 13 I894M,
1457 6
1453 5
1455 5
1447 11
1351 13 M1351V, M1351R,
1449 9 Y1449S, Y1449C,
1452 7
1461 10 T1461S,
926 14
1344 12 F1344L, F1344S,
1450 7
1411 12
1451 5 V1451D, V1451L,
934 12
1458 5 S1458Y,
935 15 L935P,
897 12 G897R, G897E,
1348 10 F1348L,
1464 14 L1464P, c.4389_4396delCCTCTTTA,
927 13 N927S, N927K,
1349 14
1422 12 M1422R,
1418 7
892 8 F892I,
1341 13
898 13
893 12 R893C, R893H,
1462 10
1412 9 L1412F,
1408 15 G1408R,
889 12
1420 13 G1420P, G1420D, G1420R, G1420V,
843 12 T843A,
1456 7
930 14 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 6 c.4376_4379delTCTT,
1460 10 F1460L,
1425 11
1454 0
1446 14
1424 13 I1424V,
1448 10 I1448L, I1448T,
1409 14 Y1409C, Y1409X,
1421 9
847 14
1345 11 W1345C,
846 12 L846R,
1416 6 A1416E, c.4245+1G>A, c.4245+2T>A, A1416G, c.4245+1G>C,
1347 14
1415 7
1428 15 A1428S, A1428V,
850 14 c.2549_2550insTG, V850M,
1419 13 K1419E,
1414 12 Q1414H,
931 11
1402 15
1463 11 N1463Y,
1413 11