SCN5A Variant L224I Detail

We estimate the penetrance of LQTS for SCN5A L224I around 34% and the Brugada syndrome penetrance around 18%. SCN5A L224I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L224I is not present in gnomAD. L224I has been functionally characterized in 0 papers. This residue is located in a Mild_Hotspot region for Brugada syndrome and a 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 (1 with LQTS). These data combined with observations of carriers lead us to estimate the LQTS penetrance for SCN5A L224I around 34% (1/10) and the Brugada syndrome penetrance around 18% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.899 18 44
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 1 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.

L224I has 59 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 10 I848F,
223 4 V223L,
856 9 V856L,
859 12
231 14 c.692_693delCA,
198 13
193 10 W193R, W193X,
164 15 F164L,
195 10
228 9 K228R,
138 14 M138I,
925 14 I925F,
227 6 L227P,
142 14
197 10
229 11
216 14 S216L, S216X,
851 10 F851L, c.2552_2553dupGT, c.2550_2551dupGT, p.F851CfsX19,
221 6
196 6
852 6
854 12 c.2559delT,
222 8 R222X, R222Q, R222L,
224 0 L224F,
845 14 c.2533delG,
857 12 G857D,
191 15
849 10
226 6 A226G, A226V,
921 14
922 15 V922I,
860 13 p.L860fsx89,
858 14 M858L,
144 11
217 11
918 14
855 10
230 12 I230T, I230V, I230M,
199 9 S199T,
148 11
204 12 A204T, c.611+3_611+4dupAA, c.611+1G>A, A204V,
847 14
203 9
192 12
168 13
202 12 I202T,
194 13
141 11 I141N, I141V,
853 10
201 11
219 12 c.656_657insATTCA, R219H, p.R219HfsX11, R219C,
225 7 R225W, R225Q,
218 12
207 14
850 13 V850M, c.2549_2550insTG,
200 6
145 11
140 15
220 9 T220I,