SCN5A Variant L177V Detail

We estimate the penetrance of LQTS for SCN5A L177V around 3% and the Brugada syndrome penetrance around 54%. SCN5A L177V was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L177V is not present in gnomAD. L177V 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 L177V around 3% (0/10) and the Brugada syndrome penetrance around 54% (5/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.734 84 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.

L177V has 40 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 10 F170I,
126 12 K126E,
175 8 K175N,
113 10 V113A, V113I,
129 13
194 14
188 11
178 5 A178G,
128 10 c.381dupT,
117 14
179 8 R179Q, R179X,
119 11 P119S, P119L,
169 12
177 0 L177P,
123 9 A123G, A123V,
121 6 R121W, R121Q,
198 13
127 10
124 6 A124D,
118 9
125 8 V125L,
181 8
176 5
172 8
174 5 V174I,
185 11 A185T, A185V,
133 13
115 10 S115G,
182 12 C182Y, C182R,
173 5
112 12 Y112C,
114 7
184 10 H184R,
116 11
187 14 T187I, T187S,
180 6 G180V,
120 8
183 13
122 11
171 11