SCN5A Variant I450V Detail

We estimate the penetrance of LQTS for SCN5A I450V around 6% and the Brugada syndrome penetrance around 21%. SCN5A I450V was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I450V is not present in gnomAD. I450V 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 I450V around 6% (0/10) and the Brugada syndrome penetrance around 21% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.289 29 6
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.

I450V has 31 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
435 15
436 14
437 14 A437V,
438 13 M438L, M438T,
439 13 E439K, E439V,
440 12
441 11 L441F,
442 11
443 10
444 9 E444fsX14,
445 8 H445Y, H445Q, H445D,
446 8 E446K,
447 7 A447G, c.1338+2T>A, A447S, c.1339-24G>A,
448 5
449 4 T449A, Y449C,
450 0
451 4
452 5 G452D,
453 7 V453M,
454 8
455 8
456 9 V456M,
457 10
458 11 R458H, R458C, p.R458VfsX12,
459 11 S459G,
460 12
461 13 L461V,
462 13 E462K, E462A,
463 14 M463R, M463T,
464 14
465 15 p.P465LfsX5,