SCN5A Variant T206I Detail

We estimate the penetrance of LQTS for SCN5A T206I around 4% and the Brugada syndrome penetrance around 27%. SCN5A T206I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T206I is not present in gnomAD. T206I 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 T206I around 4% (0/10) and the Brugada syndrome penetrance around 27% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.351 40 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 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.

T206I has 33 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
203 6
208 6 E208K,
205 5 Y205X, c.612-2A>G,
168 14
158 15 K158T,
202 6 I202T,
206 0
166 14 A166T,
216 11 S216X, S216L,
214 11
221 12
161 13 E161Q, E161K,
201 9
219 11 c.656_657insATTCA, R219H, R219C, p.R219HfsX11,
211 8
169 13
217 10
222 10 R222L, R222Q, R222X,
218 6
198 14
213 12
210 9 I210T,
207 4
212 10 L212Q, L212P,
199 10 S199T,
209 5 N209S, N209T,
215 11 p.L215CfsX10,
195 15
200 10
165 11
220 12 T220I,
204 5 A204V, A204T, c.611+3_611+4dupAA, c.611+1G>A,
162 12 Y162H, Y162C,