SCN5A Variant T238I Detail

We estimate the penetrance of LQTS for SCN5A T238I around 45% and the Brugada syndrome penetrance around 15%. SCN5A T238I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T238I is not present in gnomAD. T238I has been functionally characterized in 0 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a 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 (2 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A T238I around 45% (2/10) and the Brugada syndrome penetrance around 15% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.939 13 59
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 2 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.

T238I 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
414 14 M414V,
939 15 L939F,
937 10
839 12 L839P,
842 9
240 7 V240M,
231 12 c.692_693delCA,
418 11 E418K,
237 6
836 14 V836M,
234 10 P234S,
417 10
934 13
933 10
246 12
412 13 V412D,
245 11 Q245K,
845 11 c.2533delG,
232 14 V232F, V232I,
244 11
415 10 A415T,
940 11 S940N,
420 6
938 14
241 7
235 5 G235R, c.704-1G>C, c.703+1G>A,
840 11
843 13 T843A,
419 6 Q419X,
930 13 c.2788-6C>T, c.2787+17_2787+18insACACACACACACACACACACACA,
423 7
837 10
239 4 I239V, I239V ,
230 11 I230M, I230T, I230V,
242 7 A242D,
929 14
416 7 Y416C,
413 13 A413T, A413E,
841 8 p.N841TfsX2, N841K,
236 6
941 13 S941F, S941N,
846 15 L846R,
936 11
238 0
233 10
838 8
422 9
421 11
844 13 L844RfsX3,
243 9
835 12 S835A, S835L,