SCN5A Variant A178T Detail

We estimate the penetrance of LQTS for SCN5A A178T around 4% and the Brugada syndrome penetrance around 52%. SCN5A A178T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. A178T is not present in gnomAD. A178T has been functionally characterized in 0 papers. This residue is located in a 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 (5 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 A178T around 4% (0/10) and the Brugada syndrome penetrance around 52% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.942 78 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 10 0 5 - -
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.

A178T has 45 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
170 12 F170I,
126 10 K126E,
175 7 K175N,
197 14
113 11 V113A, V113I,
129 9
194 12
188 9
178 0 A178G,
128 7 c.381dupT,
117 13
179 3 R179Q, R179X,
119 12 P119S, P119L,
169 15
177 5 L177P,
189 15
123 9 A123G, A123V,
121 5 R121W, R121Q,
198 13
127 9
124 6 A124D,
118 11
125 5 V125L,
181 11
176 6
172 10
174 6 V174I,
185 11 A185T, A185V,
133 12
115 10 S115G,
130 13
182 13 C182Y, C182R,
173 9
112 11 Y112C,
114 8
184 8 H184R,
191 15
116 10
187 12 T187I, T187S,
180 6 G180V,
134 13 N134S,
120 10
183 13
122 9
171 11