SCN5A Variant I1448S Detail

We estimate the penetrance of LQTS for SCN5A I1448S around 6% and the Brugada syndrome penetrance around 39%. SCN5A I1448S was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I1448S is not present in gnomAD. I1448S has been functionally characterized in 0 papers. This residue is located in a 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 (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 I1448S around 6% (0/10) and the Brugada syndrome penetrance around 39% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.947 55 3
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.

I1448S has 51 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 15 I891N, I891T,
888 9
1355 12
890 15 I890T,
896 15 C896S,
895 15 L895F,
1352 13
1445 8 Y1445H,
1457 14
1453 10
1455 10
1447 4
1444 9 L1444I,
1351 11 M1351V, M1351R,
1449 6 Y1449C, Y1449S,
1452 6
1429 11
806 14 V806M,
1450 7
887 14
1451 5 V1451D, V1451L,
886 13 H886Q, H886P,
1458 15 S1458Y,
851 15 c.2552_2553dupGT, c.2550_2551dupGT, F851L, p.F851CfsX19,
1348 11 F1348L,
1431 15 S1431C,
1422 15 M1422R,
892 10 F892I,
1356 13 c.4066_4068delTT,
1412 14 L1412F,
889 10
843 14 T843A,
1456 12
1459 14 c.4376_4379delTCTT,
1425 10
1454 10
1446 6
1424 15 I1424V,
1448 0 I1448L, I1448T,
884 12
809 14
1421 14
885 9
847 13
1443 12 N1443S,
846 15 L846R,
879 15 W879R,
883 15
1415 13
1428 12 A1428S, A1428V,
850 14 c.2549_2550insTG, V850M,