SCN5A Variant I849T Detail

We estimate the penetrance of LQTS for SCN5A I849T around 22% and the Brugada syndrome penetrance around 31%. SCN5A I849T was found in a total of 0 carriers in 0 papers and/or in gnomAD: 0 had Brugada syndrome, 0 had LQTS. I849T is not present in gnomAD. I849T 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 (3 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 I849T around 22% (1/10) and the Brugada syndrome penetrance around 31% (3/10).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density BrS (%) Penetrance Density LQT3 (%)
NA NA NA 0.954 41 27
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 1 3 - -
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.

I849T has 73 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
891 9 I891T, I891N,
888 11
848 5 I848F,
223 11 V223L,
856 11 V856L,
890 14 I890T,
919 13
896 14 C896S,
895 9 L895F,
839 15 L839P,
842 10
894 12 I894M,
247 14 V247L,
240 11 V240M,
231 14 c.692_693delCA,
1455 15
193 14 W193R, W193X,
926 7
228 13 K228R,
928 13 L928P,
925 7 I925F,
227 8 L227P,
887 13
934 14
933 12
229 11
246 14
851 8 c.2552_2553dupGT, F851L, c.2550_2551dupGT, p.F851CfsX19,
196 15
221 14
924 11 V924I,
927 11 N927S, N927K,
852 6
854 9 c.2559delT,
224 10 L224F,
845 6 c.2533delG,
857 13 G857D,
232 15 V232F, V232I,
244 13
892 12 F892I,
849 0
226 9 A226G, A226V,
921 10
922 8 V922I,
241 14
920 14
840 13
889 15
843 10 T843A,
930 8 c.2788-6C>T, c.2787+17_2787+18insACACACACACACACACACACACA,
1459 14 c.4376_4379delTCTT,
918 12
855 11
239 12 I239V, I239V ,
230 9 I230M, I230T, I230V,
242 14 A242D,
148 15
929 10
884 14
841 13 p.N841TfsX2, N841K,
236 14
847 6
846 5 L846R,
233 13
853 6
225 14 R225Q, R225W,
923 12
844 10 L844RfsX3,
850 5 c.2549_2550insTG, V850M,
243 10
932 14
145 13
931 11