Pharmacogenetics of antiepileptic drug efficacy in childhood absence epilepsy
Year: 2017
Type: article
Abstract: Objective To determine whether common polymorphisms in CACNA1G, CACNA1H, CACNA1I, and ABCB1 are associated with differential short‐term seizure outcome in childhood absence epilepsy (CAE). Methods Four hundred forty‐six CAE children in a randomized double‐blind trial of ethosuximide, lamotrigine, and valproate had short‐term seizure outcome determined. Associations between polymorphisms (minor allele frequency ≥ 15%) in 4 genes and seizure outcomes were assessed. In vitro electrophysiology on transfected CACNA1H channels determined impact of 1 variant on T‐type calcium channel responsiveness to ethosuximide. Results Eighty percent (357 of 446) of subjects had informative short‐term seizure status (242 seizure free, 115 not seizure free). In ethosuximide subjects, 2 polymorphisms (CACNA1H rs61734410/P640L, CACNA1I rs3747178) appeared more commonly among not–seizure‐free participants (p = 0.011, odds ratio [OR] = 2.63, 95% confidence limits [CL] = 1.25–5.56; p = 0.026, OR = 2.38, 95% CL = 1.11–5.00). In lamotrigine subjects, 1 ABCB1 missense polymorphism (rs2032582/S893A; p = 0.015, OR = 2.22, 95% CL = 1.16–4.17) was more common in not–seizure‐free participants, and 2 CACNA1H polymorphisms (rs2753326, rs2753325) were more common in seizure‐free participants (p = 0.038, OR = 0.52, 95% CL = 0.28–0.96). In valproate subjects, no common polymorphisms were associated with seizure status. In vitro electrophysiological studies showed no effect of the P640L polymorphism on channel physiology in the absence of ethosuximide. Ethosuximide's effect on rate of decay of CaV3.2 was significantly less for P640L channel compared to wild‐type channel. Interpretation Four T‐type calcium channel variants and 1 ABCB1 transporter variant were associated with differential drug response in CAE. The in vivo P640L variant's ethosuximide effect was confirmed by in vitro electrophysiological studies. This suggests that genetic variation plays a role in differential CAE drug response. Ann Neurol 2017;81:444–453
Source: Annals of Neurology
DOI: 10.1002/ana.24886
Authors: Tracy A. Glauser, Katherine Holland, Valerie P. O’Brien, Mehdi Keddache, Lisa J. Martin, Peggy O. Clark, Avital Cnaan, Dennis Dlugos, Deborah G. Hirtz, Shlomo Shinnar, Gregory Grabowski, for the Childhood Absence Epilepsy Study Group
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
Awards: General Clinical Research Center, The Intellectual and Developmental Disabilities Research Center at CHOP/Penn, G2376935796, Sodium Channel Gene Variation in the Treatment of Epilepsy, G3574384961, Childhood Absence Epilepsy: Coordinating Center, Clinical and Translational Science Institute at Children's National, G736570329, CHMCC Pediatric Pharmacology Research Unit, G9000034520, G9000074227, G9000251140, G9000338499
OpenAlex ID: W2600679849