SCN5A Variant D501G Detail

We estimate the penetrance of LQTS for SCN5A D501G around 5% and the Brugada syndrome penetrance around 46%. SCN5A D501G was found in a total of 1 carriers in 3 papers and/or in gnomAD: 1 had Brugada syndrome, 0 had LQTS. D501G is not present in gnomAD. D501G has been functionally characterized in 3 papers. This residue is located in a 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 (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 D501G around 5% (0/11) and the Brugada syndrome penetrance around 46% (5/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
-4.18 0.992 0.12 0.881 59 2
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
24631775 2014 1 0 0 1 SIDS
20129283 2010 1 0 1 0
29759671 2018 1 0 1 0
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 1 -
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.

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)
29759671 2018
24631775 2014
20129283 2010

D501G 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
486 15 T486S, T486A,
487 14
488 14
489 13
490 13 G490A, G490E,
491 12 E491G,
492 11
493 11 R493K,
494 10
495 9
496 8 K496M, K496N,
497 8 S497C,
498 7
499 5
500 4 E500K,
501 0 D501G,
502 4
503 5 P503S,
504 7 R504T,
505 8 A505E,
506 8 M506K,
507 9 p.N507_L515dup,
508 10
509 11
510 11
511 12
512 13 T512I,
513 13 R513P, R513C, R513H, c.1537delC,
514 14 G514C,
515 14
516 15