SCN5A Variant I230L Detail

We estimate the penetrance of LQTS for SCN5A I230L around 5% and the Brugada syndrome penetrance around 19%. SCN5A I230L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I230L is not present in gnomAD. I230L 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 I230L around 5% (0/10) and the Brugada syndrome penetrance around 19% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.797 21 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.

I230L has 57 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 6 I848F,
223 13 V223L,
839 14 L839P,
842 11
240 7 V240M,
231 5 c.692_693delCA,
193 9 W193X, W193R,
926 15
237 10
228 7 K228R,
138 10 M138I,
925 14 I925F,
227 6 L227P,
137 14 I137V,
234 10 P234S,
142 11
197 13
933 15
229 5
851 12 c.2552_2553dupGT, c.2550_2551dupGT, F851L, p.F851CfsX19,
196 12
852 11
224 12 L224F,
845 6 c.2533delG,
232 7 V232F, V232I,
244 12
191 15
134 14 N134S,
849 9
226 8 A226G, A226V,
241 11
235 10 c.703+1G>A, G235R, c.704-1G>C,
840 11
843 11 T843A,
930 13 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
837 14
239 9 I239V , I239V,
230 0 I230V, I230M, I230T,
139 14 p.I137_C139dup,
242 12 A242D,
841 9 N841K, p.N841TfsX2,
236 6
847 10
846 11 L846R,
192 13
238 11
233 5
838 13
194 14
141 11 I141N, I141V,
135 15 M135V,
853 14
225 11 R225Q, R225W,
844 8 L844RfsX3,
850 13 c.2549_2550insTG, V850M,
243 11
145 13