SCN5A Variant V174L Detail

We estimate the penetrance of LQTS for SCN5A V174L around 3% and the Brugada syndrome penetrance around 21%. SCN5A V174L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. V174L is not present in gnomAD. V174L 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 (2 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 V174L around 3% (0/10) and the Brugada syndrome penetrance around 21% (2/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.556 27 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 13 0 2 - -
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.

V174L 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
121 9 R121W, R121Q,
198 11
124 6 A124D,
131 14
115 15 S115G,
114 12
130 12
170 6 F170I,
184 13 H184R,
122 13
171 6
137 11 I137V,
197 12
129 10
119 14 P119L, P119S,
169 9
177 5 L177P,
123 9 A123G, A123V,
127 7
125 8 V125L,
174 0 V174I,
133 8
132 14 c.393-5C>A,
116 15
134 11 N134S,
166 12 A166T,
179 9 R179Q, R179X,
172 6
185 13 A185V, A185T,
165 14
180 10 G180V,
120 11
126 11 K126E,
136 13 L136P,
168 12
175 5 K175N,
194 12
188 11
167 11
178 6 A178G,
128 6 c.381dupT,
201 13
118 14
181 13
176 6
173 5
187 15 T187S, T187I,