SCN5A Variant L196Q Detail

We estimate the penetrance of LQTS for SCN5A L196Q around 5% and the Brugada syndrome penetrance around 16%. SCN5A L196Q was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L196Q is not present in gnomAD. L196Q 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 L196Q around 5% (0/10) and the Brugada syndrome penetrance around 16% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.983 13 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.

L196Q has 48 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 14 I848F,
223 10 V223L,
856 15 V856L,
240 14 V240M,
231 13 c.692_693delCA,
198 7
193 6 W193X, W193R,
195 5
228 8 K228R,
138 13 M138I,
227 7 L227P,
171 12
137 14 I137V,
197 5
229 12
221 10
196 0
190 13 R190Q, R190W, R190L, R190G,
169 15
189 9
852 12
222 12 R222Q, R222L, R222X,
224 6 L224F,
244 15
191 9
849 15
226 9 A226V, A226G,
144 15
217 15
172 13
230 12 I230M, I230V, I230T,
185 14 A185T, A185V,
199 6 S199T,
204 13 c.611+1G>A, A204V, A204T, c.611+3_611+4dupAA,
203 10
192 6
168 12
175 12 K175N,
202 10 I202T,
194 7
141 12 I141N, I141V,
188 11
201 9
225 7 R225Q, R225W,
218 14
200 6
187 13 T187S, T187I,
220 14 T220I,