SCN5A Variant L839Q Detail

We estimate the penetrance of LQTS for SCN5A L839Q around 13% and the Brugada syndrome penetrance around 40%. SCN5A L839Q was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. L839Q is not present in gnomAD. L839Q has been functionally characterized in 0 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 (4 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 L839Q around 13% (0/10) and the Brugada syndrome penetrance around 40% (4/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.985 57 13
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 11 0 4 - -
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.

L839Q has 59 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
848 14 I848F,
939 13 L939F,
937 7
839 0 L839P,
842 5
1457 13
240 14 V240M,
1455 10
1452 14
1461 13 T1461S,
836 6 V836M,
234 11 P234S,
1451 15 V1451D, V1451L,
934 7
1458 14 S1458Y,
933 10
935 12 L935P,
1464 13 L1464P, c.4389_4396delCCTCTTTA,
845 10 c.2533delG,
830 14
833 9 G833R,
940 11 S940N,
849 15
831 11
420 14
938 9
235 12 G235R, c.704-1G>C, c.703+1G>A,
840 4
942 11
843 6 T843A,
1456 10
930 11 c.2787+17_2787+18insACACACACACACACACACACACA, c.2788-6C>T,
1459 11 c.4376_4379delTCTT,
834 10 N834D,
1460 9 F1460L,
837 6
239 10 I239V, I239V ,
1454 14
230 14 I230T, I230M, I230V,
242 15 A242D,
416 12 Y416C,
841 7 N841K, p.N841TfsX2,
236 13
847 12
941 10 S941F, S941N,
846 10 L846R,
936 11
238 12
233 11
838 5
844 9 L844RfsX3,
829 13
243 15
932 14
832 8
835 5 S835A, S835L,
828 13 L828V,
931 12
1463 13 N1463Y,