SCN5A Variant I176N Detail

We estimate the penetrance of LQTS for SCN5A I176N around 4% and the Brugada syndrome penetrance around 49%. SCN5A I176N was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I176N is not present in gnomAD. I176N 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 (4 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 I176N around 4% (0/10) and the Brugada syndrome penetrance around 49% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.973 72 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 11 0 4 - -
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.

I176N has 47 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 11 F170I,
168 14
175 6 K175N,
202 13 I202T,
197 11
113 10 V113I, V113A,
129 14
194 10
188 7
178 6 A178G,
190 15 R190L, R190Q, R190G, R190W,
128 10 c.381dupT,
201 13
179 7 R179Q, R179X,
169 11
177 5 L177P,
189 11
123 13 A123V, A123G,
121 9 R121Q, R121W,
198 8
127 13
124 10 A124D,
118 14
125 11 V125L,
181 7
176 0
172 6
174 6 V174I,
185 7 A185T, A185V,
199 14 S199T,
133 14
115 13 S115G,
186 12
195 14
122 15
182 9 C182R, C182Y,
173 6
112 13 Y112C,
114 8
184 8 H184R,
191 13
116 14
187 10 T187S, T187I,
180 5 G180V,
120 13
183 11
171 9