SCN5A Variant T229I Detail

We estimate the penetrance of LQTS for SCN5A T229I around 7% and the Brugada syndrome penetrance around 19%. SCN5A T229I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T229I is not present in gnomAD. T229I 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 T229I around 7% (0/10) and the Brugada syndrome penetrance around 19% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.952 19 4
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 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.

T229I has 55 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
848 6 I848F,
223 11 V223L,
842 14
240 12 V240M,
231 6 c.692_693delCA,
193 11 W193X, W193R,
237 14
228 6 K228R,
138 6 M138I,
227 6 L227P,
143 12
171 15
137 11 I137V,
234 12 P234S,
142 7
197 12
229 0
851 10 c.2552_2553dupGT, c.2550_2551dupGT, F851L, p.F851CfsX19,
196 12
852 10
222 15 R222Q, R222L, R222X,
224 11 L224F,
845 9 c.2533delG,
232 6 V232I, V232F,
134 12 N134S,
849 11
226 5 A226V, A226G,
235 13 c.703+1G>A, c.704-1G>C, G235R,
840 13
843 13 T843A,
144 11
855 14
239 13 I239V, I239V ,
230 5 I230M, I230V, I230T,
139 10 p.I137_C139dup,
148 13
841 11 p.N841TfsX2, N841K,
236 10
847 10
146 13 V146A, V146M,
846 13 L846R,
136 14 L136P,
168 14
233 7
194 14
141 7 I141N, I141V,
135 12 M135V,
853 14
225 8 R225Q, R225W,
844 9 L844RfsX3,
850 13 c.2549_2550insTG, V850M,
243 15
200 14
145 9
140 11