SCN5A Variant R975Q Detail

We estimate the penetrance of LQTS for SCN5A R975Q around 2% and the Brugada syndrome penetrance around 7%. SCN5A R975Q was found in a total of 11 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. R975Q is present in 11 alleles in gnomAD. R975Q has been functionally characterized in 0 papers. This residue is located in a Mild_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 (1 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 R975Q around 2% (0/21) and the Brugada syndrome penetrance around 7% (1/21).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-0.99 0.999 -0.07 0.512 13 5
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: - 11 11 0 0 -
VARIANT FEATURES ALONE: - 15 14 0 1 - -
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.

R975Q 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
960 15 Q960K,
961 14
962 14
963 13
964 13 A964G,
965 12 R965C, R965L, R965H,
966 11
967 11 Q967R,
968 10
969 9 G969S, G969C,
970 8
971 8 R971H, R971C,
972 7 c.2914_2923delTTTGTCAAGC,
973 5
974 4 K974D,
975 0 R975Q, R975W,
976 4
977 5
978 7
979 8 D979H,
980 8
981 9 C981F,
982 10 C982R,
983 11 G983D,
984 11
985 12
986 13 R986L, R986Q, R986W,
987 13
988 14 R988W, R988Q,
989 14
990 15