SCN5A Variant N194I Detail

We estimate the penetrance of LQTS for SCN5A N194I around 5% and the Brugada syndrome penetrance around 12%. SCN5A N194I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. N194I is not present in gnomAD. N194I has been functionally characterized in 0 papers. This residue is located in a Non_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 N194I around 5% (0/10) and the Brugada syndrome penetrance around 12% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.929 7 2
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.

N194I has 49 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
231 12 c.692_693delCA,
198 6
193 6 W193X, W193R,
195 7
184 11 H184R,
228 9 K228R,
138 14 M138I,
183 15
227 12 L227P,
171 10
137 13 I137V,
197 5
229 14
129 15
196 7
190 10 R190Q, R190W, R190L, R190G,
169 14
177 14 L177P,
189 7
224 13 L224F,
174 12 V174I,
133 15
182 15 C182Y, C182R,
134 13 N134S,
191 4
226 14 A226V, A226G,
179 11 R179X, R179Q,
172 10
230 14 I230M, I230V, I230T,
185 10 A185T, A185V,
199 9 S199T,
180 12 G180V,
203 15
192 6
168 13
175 8 K175N,
202 13 I202T,
194 0
141 15 I141N, I141V,
188 5
178 12 A178G,
128 12 c.381dupT,
201 11
225 10 R225Q, R225W,
176 10
186 11
173 14
200 11
187 8 T187S, T187I,