SCN5A Variant I233N Detail

We estimate the penetrance of LQTS for SCN5A I233N around 9% and the Brugada syndrome penetrance around 19%. SCN5A I233N was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I233N is not present in gnomAD. I233N 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 I233N around 9% (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 0.961 19 7
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.

I233N has 44 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 9 I848F,
937 15
839 11 L839P,
842 9
240 9 V240M,
231 6 c.692_693delCA,
193 13 W193R, W193X,
237 10
228 11 K228R,
138 11 M138I,
227 11 L227P,
836 12 V836M,
234 5 P234S,
142 12
933 15
229 7
851 15 p.F851CfsX19, c.2550_2551dupGT, c.2552_2553dupGT, F851L,
845 8 c.2533delG,
232 5 V232F, V232I,
134 15 N134S,
849 13
226 12 A226G, A226V,
241 13
235 6 G235R, c.704-1G>C, c.703+1G>A,
840 8
843 10 T843A,
930 15 c.2788-6C>T, c.2787+17_2787+18insACACACACACACACACACACACA,
837 9
239 9 I239V, I239V ,
230 5 I230M, I230V, I230T,
139 14 p.I137_C139dup,
242 14 A242D,
841 5 N841K, p.N841TfsX2,
236 5
847 11
846 12 L846R,
238 10
233 0
838 10
141 14 I141V, I141N,
135 14 M135V,
844 6 L844RfsX3,
243 13
835 14 S835A, S835L,