SCN5A Variant c.3318dupC Detail

We estimate the penetrance of LQTS for SCN5A c.3318dupC around 29% and the Brugada syndrome penetrance around 7%. SCN5A c.3318dupC was found in a total of 0 carriers in 1 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. c.3318dupC is not present in gnomAD. c.3318dupC has been functionally characterized in 1 papers. This residue is located in a Non_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 (0 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.3318dupC around 29% (1/10) and the Brugada syndrome penetrance around 7% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA None 0 36
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
23349452 2013 1 0 0 1 DCM
LITERATURE, COHORT, AND GNOMAD: - 0 0 0 0 -
VARIANT FEATURES ALONE: - 15 14 1 0 - -
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)
23349452 2013

c.3318dupC has 31 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
1092 15
1093 14
1094 14
1095 13 W1095C, W1095X,
1096 13 S1096C, S1096G,
1097 12 Q1097H, c.3288+2delT,
1098 11 V1098L, V1098M,
1099 11
1100 10 A1100T, A1100V,
1101 9
1102 8 A1102T,
1103 8 S1103Y, S1103F,
1104 7
1105 5 E1105X, E1105V,
1106 4 A1106T,
1107 0 p.E1107RfsX24, E1107K, E1107X,
1108 4
1109 5 S1109G,
1110 7
1111 8
1112 8 Q1112X,
1113 9 A1113T, A1113V,
1114 10 D1114E, D1114N,
1115 11 W1115R, W1115X,
1116 11 R1116Q, R1116W,
1117 12
1118 13 Q1118X,
1119 13
1120 14
1121 14 A1121V,
1122 15