SCN5A Variant I202T Detail

We estimate the penetrance of LQTS for SCN5A I202T around 0% and the Brugada syndrome penetrance around 15%. SCN5A I202T was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I202T is present in 1 alleles in gnomAD. I202T 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 (1 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 I202T around 0% (0/11) and the Brugada syndrome penetrance around 15% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
0.6 0 0.32 0.399 23 1
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: - 1 1 0 0 -
VARIANT FEATURES ALONE: - 15 14 0 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.

I202T has 45 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
223 14 V223L,
198 7
164 15 F164L,
209 10 N209T, N209S,
195 9
171 13
197 10
216 15 S216X, S216L,
221 11
196 10
169 10
189 11
222 11 R222L, R222Q, R222X,
224 12 L224F,
205 6 c.612-2A>G, Y205X,
206 6
166 13 A166T,
211 15
217 12
172 10
185 13 A185V, A185T,
199 5 S199T,
165 10
204 6 c.611+1G>A, c.611+3_611+4dupAA, A204T, A204V,
162 15 Y162C, Y162H,
203 5
208 10 E208K,
192 15
168 11
175 14 K175N,
202 0 I202T,
194 13
188 13
167 14
161 15 E161Q, E161K,
201 5
219 14 R219C, c.656_657insATTCA, p.R219HfsX11, R219H,
225 12 R225Q, R225W,
218 9
176 13
207 9
215 15 p.L215CfsX10,
173 13
200 6
220 14 T220I,