SCN5A Variant Q998L Detail

We estimate the penetrance of LQTS for SCN5A Q998L around 7% and the Brugada syndrome penetrance around 7%. SCN5A Q998L was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. Q998L is not present in gnomAD. Q998L 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 (0 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 Q998L around 7% (0/10) 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 0.315 3 8
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 15 0 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.

Q998L 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
983 15 G983D,
984 14
985 14
986 13 R986L, R986Q, R986W,
987 13
988 12 R988W, R988Q,
989 11
990 11
991 10 K991E, K991T,
992 9
993 8 A993S, A993T,
994 8 A994V, A994T,
995 7 L995F,
996 5 A996T,
997 4 A997T, A997S, A997D,
998 0
999 4 G999D,
1000 5 Q1000L, p.Gln1000del, Q1000X,
1001 7
1002 8 P1002S, c.3005-3012delCCAGCTGG,
1003 8
1004 9 C1004R,
1005 10 I1005V, I1005T,
1006 11 A1006S,
1007 11 T1007I, T1007N,
1008 12 P1008S,
1009 13
1010 13
1011 14 P1011L, P1011S,
1012 14
1013 15