SCN5A Variant T220A Detail

We estimate the penetrance of LQTS for SCN5A T220A around 9% and the Brugada syndrome penetrance around 17%. SCN5A T220A was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. T220A is not present in gnomAD. T220A 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 T220A around 9% (0/10) and the Brugada syndrome penetrance around 17% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.842 16 8
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.

T220A has 57 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 7 V223L,
856 5 V856L,
919 15
862 11
859 5
149 15
863 12
227 14 L227P,
887 14
864 14
216 6 S216X, S216L,
851 13 c.2552_2553dupGT, c.2550_2551dupGT, F851L, p.F851CfsX19,
221 4
196 14
852 10
854 11 c.2559delT,
222 7 R222Q, R222L, R222X,
224 9 L224F,
213 14
857 8 G857D,
881 13
226 13 A226V, A226G,
921 14
860 6 p.L860fsx89,
206 12
214 13
858 9 M858L,
144 14
217 4
918 12
855 8
917 14 L917R, L917V,
913 14
199 13 S199T,
148 11
884 15
204 11 c.611+1G>A, A204V, A204T, c.611+3_611+4dupAA,
910 14 S910L,
203 9
208 15 E208K,
202 14 I202T,
853 11
161 14 E161K, E161Q,
201 14
219 6 R219H, p.R219HfsX11, R219C, c.656_657insATTCA,
225 13 R225Q, R225W,
151 13
218 7
207 11
915 14 C915R,
212 13 L212Q, L212P,
215 9 p.L215CfsX10,
914 11
200 10
861 9 p.F861WfsX90, c.2582_2583delTT,
145 14
220 0 T220I,