SCN5A Variant M148I Detail

We estimate the penetrance of LQTS for SCN5A M148I around 4% and the Brugada syndrome penetrance around 11%. SCN5A M148I was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. M148I is not present in gnomAD. M148I has been functionally characterized in 0 papers. This residue is located in a Non_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 M148I around 4% (0/10) and the Brugada syndrome penetrance around 11% (1/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.926 6 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 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.

M148I has 68 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
888 14
154 12 P154L,
848 13 I848F,
223 7 V223L,
856 10 V856L,
862 14
859 10
153 12
149 5
147 5
164 10 F164L,
138 15 M138I,
227 13 L227P,
887 12
143 9
142 10
156 11 W156X, W156R,
158 13 K158T,
229 13
163 14 c.486delC,
216 15 S216L, S216X,
851 8 F851L, c.2552_2553dupGT, c.2550_2551dupGT, p.F851CfsX19,
221 13
852 10
854 10 c.2559delT,
222 7 R222X, R222Q, R222L,
224 11 L224F,
155 13
857 12 G857D,
150 8
157 12 T157I,
882 14
160 11 p.V160fs,
881 14
849 15
226 10 A226G, A226V,
860 14 p.L860fsx89,
858 9 M858L,
144 5
217 15
855 6
139 14 p.I137_C139dup,
148 0
165 14
884 9
204 13 A204T, c.611+3_611+4dupAA, c.611+1G>A, A204V,
162 15 Y162C, Y162H,
885 13
146 7 V146A, V146M,
847 14
203 15
168 13
152 9 D152N,
141 10 I141N, I141V,
853 13
161 10 E161K, E161Q,
219 9 c.656_657insATTCA, R219H, p.R219HfsX11, R219C,
225 11 R225W, R225Q,
151 6
218 14
159 15 Y159C, Y159X,
883 12
207 14
850 13 V850M, c.2549_2550insTG,
200 13
145 5
140 12
220 11 T220I,