SCN5A Variant I244L Detail

We estimate the penetrance of LQTS for SCN5A I244L around 44% and the Brugada syndrome penetrance around 10%. SCN5A I244L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I244L is not present in gnomAD. I244L has been functionally characterized in 0 papers. This residue is located in a Non_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 (0 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 I244L around 44% (2/10) and the Brugada syndrome penetrance around 10% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.815 4 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 13 2 0 - -
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.

I244L has 46 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 13 M414V,
842 14
249 9 K249X,
247 6 V247L,
240 6 V240M,
231 14 c.692_693delCA,
193 10 W193R, W193X,
418 12 E418K,
926 14
250 11
237 10
928 15 L928P,
925 11 I925F,
227 13 L227P,
933 12
246 6
412 11 V412D,
196 15
924 13 V924I,
245 5 Q245K,
845 13 c.2533delG,
244 0
415 10 A415T,
191 13
849 13
420 14
248 6
241 4
235 14 G235R, c.704-1G>C, c.703+1G>A,
419 10 Q419X,
930 12 c.2788-6C>T, c.2787+17_2787+18insACACACACACACACACACACACA,
239 9 I239V, I239V ,
230 12 I230M, I230V, I230T,
251 12
242 6 A242D,
929 10
416 12 Y416C,
413 14 A413E, A413T,
236 11
408 15
192 11
238 11
422 14
411 12 V411M,
243 5
932 15