SCN5A Variant c.2550_2551dupGT Detail

We estimate the penetrance of LQTS for SCN5A c.2550_2551dupGT around 27% and the Brugada syndrome penetrance around 36%. SCN5A c.2550_2551dupGT was found in a total of 1 carriers in 1 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. c.2550_2551dupGT is not present in gnomAD. c.2550_2551dupGT has been functionally characterized in 1 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 (2 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 c.2550_2551dupGT around 27% (1/11) and the Brugada syndrome penetrance around 36% (3/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 39 43
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
20129283 2010 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
VARIANT FEATURES ALONE: - 15 12 1 2 - -
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.

Functional Data

Peak and late/persistent current are relative to wildtype (100% being no different from wildtype). V0.5 act/inact are the voltages at which half of the maximal current is reached during an activation and inactivation protocol, each is in units of mV and relative to wildtype.
PubMed ID Year Cell Type Peak Current (%WT) V1/2 Act. (mV) V1/2 Inact. (mV) Late/Persistent Current (%WT)
20129283 2010

c.2550_2551dupGT has 64 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
891 10 I891T, I891N,
888 8
848 6 I848F,
223 7 V223L,
856 9 V856L,
890 13 I890T,
859 13
895 13 L895F,
894 14 I894M,
1447 14
149 9
147 12
926 14
228 13 K228R,
138 15 M138I,
925 14 I925F,
227 10 L227P,
143 13
887 9
1451 14 V1451L, V1451D,
142 11
886 14 H886P, H886Q,
229 10
851 0 c.2550_2551dupGT, F851L, p.F851CfsX19, c.2552_2553dupGT,
221 13
852 5
854 6 c.2559delT,
222 12 R222L, R222Q, R222X,
224 10 L224F,
845 11 c.2533delG,
857 10 G857D,
150 13
892 12 F892I,
881 13
849 8
226 7 A226G, A226V,
922 13 V922I,
860 14 p.L860fsx89,
889 12
843 13 T843A,
858 10 M858L,
144 10
918 15
855 6
230 12 I230V, I230M, I230T,
148 8
1448 15 I1448T, I1448L,
884 7
885 11
146 10 V146M, V146A,
847 7
846 10 L846R,
233 15
152 13 D152N,
141 11 I141V, I141N,
853 8
219 15 c.656_657insATTCA, R219C, R219H, p.R219HfsX11,
225 12 R225Q, R225W,
151 12
883 13
844 11 L844RfsX3,
850 6 V850M, c.2549_2550insTG,
145 7
220 13 T220I,