SCN5A Variant T140I Detail

We estimate the penetrance of LQTS for SCN5A T140I around 4% and the Brugada syndrome penetrance around 24%. SCN5A T140I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T140I is not present in gnomAD. T140I 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 T140I around 4% (0/10) and the Brugada syndrome penetrance around 24% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.867 28 0
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.

T140I has 50 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 13 V223L,
231 14 c.692_693delCA,
149 15
147 10
131 14
164 6 F164L,
170 12 F170I,
228 11 K228R,
138 7 M138I,
227 14 L227P,
171 10
143 5
137 5 I137V,
142 7
197 13
229 11
163 9 c.486delC,
169 12
222 12 R222Q, R222L, R222X,
224 15 L224F,
150 15
232 13 V232I, V232F,
133 10
157 15 T157I,
132 12 c.393-5C>A,
160 10 p.V160fs,
134 11 N134S,
226 11 A226V, A226G,
166 10 A166T,
144 7
172 14
139 5 p.I137_C139dup,
148 12
165 10
204 14 c.611+1G>A, A204V, A204T, c.611+3_611+4dupAA,
162 14 Y162H, Y162C,
146 10 V146A, V146M,
136 7 L136P,
168 7
175 15 K175N,
141 5 I141N, I141V,
135 10 M135V,
167 7
161 12 E161K, E161Q,
201 13
225 9 R225Q, R225W,
159 14 Y159C, Y159X,
200 14
145 9
140 0