SCN5A Variant K248M Detail

We estimate the penetrance of LQTS for SCN5A K248M around 21% and the Brugada syndrome penetrance around 9%. SCN5A K248M was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. K248M is not present in gnomAD. K248M has been functionally characterized in 0 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 K248M around 21% (1/10) and the Brugada syndrome penetrance around 9% (0/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.847 2 25
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 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.

K248M has 35 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
414 12 M414V,
1643 15 I1643L,
249 6 K249X,
247 5 V247L,
240 12 V240M,
254 12
193 14 W193R, W193X,
418 13 E418K,
250 8
928 15 L928P,
925 13 I925F,
933 15
246 7
412 12 V412D,
924 13 V924I,
245 5 Q245K,
244 6
415 11 A415T,
248 0
241 9
419 13 Q419X,
255 14
239 14 I239V, I239V ,
251 8
410 15 A410V,
242 10 A242D,
929 12
413 15 A413E, A413T,
408 13
253 12
192 13
1642 13 G1642E,
252 10
411 11 V411M,
243 9