SCN5A Variant A226G Detail

We estimate the penetrance of LQTS for SCN5A A226G around 4% and the Brugada syndrome penetrance around 14%. SCN5A A226G was found in a total of 1 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A226G is present in 1 alleles in gnomAD. A226G has been functionally characterized in 0 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a Mild_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 A226G around 4% (0/11) and the Brugada syndrome penetrance around 14% (1/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-3.88 0.987 -5.39 0.935 12 11
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.

A226G has 63 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 7 I848F,
223 6 V223L,
856 12 V856L,
240 14 V240M,
231 10 c.692_693delCA,
198 15
149 13
147 13
193 11 W193X, W193R,
164 13 F164L,
195 14
228 6 K228R,
138 9 M138I,
925 15 I925F,
227 4 L227P,
143 11
171 14
137 12 I137V,
142 8
197 10
229 5
851 7 p.F851CfsX19, c.2552_2553dupGT, F851L, c.2550_2551dupGT,
221 12
196 9
852 6
854 12 c.2559delT,
222 10 R222X, R222Q, R222L,
224 6 L224F,
845 10 c.2533delG,
857 15 G857D,
232 11 V232F, V232I,
134 15 N134S,
849 9
226 0 A226G, A226V,
858 15 M858L,
144 8
855 10
230 8 I230T, I230M, I230V,
199 13 S199T,
139 12 p.I137_C139dup,
148 10
884 14
204 15 c.611+3_611+4dupAA, A204V, A204T, c.611+1G>A,
236 14
146 12 V146A, V146M,
847 10
203 14
846 13 L846R,
192 14
168 12
233 12
194 14
141 6 I141V, I141N,
853 11
201 13
219 15 R219C, p.R219HfsX11, c.656_657insATTCA, R219H,
225 6 R225W, R225Q,
844 12 L844RfsX3,
850 11 c.2549_2550insTG, V850M,
200 10
145 7
140 11
220 13 T220I,