SCN5A Variant c.2549_2550insTG Detail

We estimate the penetrance of LQTS for SCN5A c.2549_2550insTG around 13% and the Brugada syndrome penetrance around 39%. SCN5A c.2549_2550insTG was found in a total of 1 carriers in 1 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. c.2549_2550insTG is not present in gnomAD. c.2549_2550insTG has been functionally characterized in 1 papers. This residue is located in a Hotspot region for Brugada syndrome and a Mild_Hotspot region for LQTS. In silico predictions, functional data (if available), and location in structure are equivalent to phenotyping 10 individuals for Brugada syndrome (3 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 c.2549_2550insTG around 13% (0/11) and the Brugada syndrome penetrance around 39% (4/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 45 18
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 0 3 - -
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.2549_2550insTG has 69 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 6 I891T, I891N,
888 6
848 7 I848F,
223 11 V223L,
856 10 V856L,
890 10 I890T,
919 12
896 11 C896S,
895 8 L895F,
842 12
894 9 I894M,
1455 13
1447 13
149 14
926 8
928 14 L928P,
925 10 I925F,
227 12 L227P,
887 9
1451 12 V1451L, V1451D,
886 14 H886P, H886Q,
933 15
229 13
851 6 c.2550_2551dupGT, F851L, p.F851CfsX19, c.2552_2553dupGT,
897 13 G897E, G897R,
924 13 V924I,
927 12 N927K, N927S,
852 6
854 6 c.2559delT,
224 13 L224F,
845 9 c.2533delG,
857 11 G857D,
902 15
892 8 F892I,
881 13
849 5
226 11 A226G, A226V,
898 15
893 13 R893C, R893H,
921 12
922 8 V922I,
860 15 p.L860fsx89,
920 15
840 15
889 10
843 11 T843A,
930 10 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 13 c.4376_4379delTCTT,
858 12 M858L,
918 12
855 9
1454 14
230 13 I230V, I230M, I230T,
148 13
929 13
1448 14 I1448T, I1448L,
884 10
885 12
847 5
846 6 L846R,
853 5
923 12
883 14
844 11 L844RfsX3,
850 0 V850M, c.2549_2550insTG,
243 14
145 12
861 15 c.2582_2583delTT, p.F861WfsX90,
931 12