%D 2018 %O Copyright © 2017 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY) (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. %P e332-e341 %V 90 %L discovery10041504 %C United States %N 4 %A M McCormack %A H Gui %A A Ingason %A D Speed %A GEB Wright %A EJ Zhang %A R Secolin %A C Yasuda %A M Kwok %A S Wolking %A F Becker %A S Rau %A A Avbersek %A K Heggeli %A C Leu %A C Depondt %A GJ Sills %A AG Marson %A P Auce %A MJ Brodie %A B Francis %A MR Johnson %A BPC Koeleman %A P Striano %A A Coppola %A F Zara %A WS Kunz %A JW Sander %A H Lerche %A KM Klein %A S Weckhuysen %A M Krenn %A LJ Gudmundsson %A K Stefánsson %A R Krause %A N Shear %A CJD Ross %A N Delanty %A . EPIGEN Consortium %A M Pirmohamed %A BC Carleton %A . Canadian Pharmacogenomics Network for Drug Safety %A F Cendes %A I Lopes-Cendes %A W-P Liao %A TJ O'Brien %A SM Sisodiya %A . EpiPGX Consortium %A S Cherny %A P Kwan %A L Baum %A . ILAE-CGC %A GL Cavalleri %T Genetic variation in CFH predicts phenytoin-induced maculopapular exanthema in European-descent patients %J Neurology %X OBJECTIVE: To characterize, among European and Han Chinese populations, the genetic predictors of maculopapular exanthema (MPE), a cutaneous adverse drug reaction common to antiepileptic drugs. METHODS: We conducted a case-control genome-wide association study of autosomal genotypes, including Class I and II human leukocyte antigen (HLA) alleles, in 323 cases and 1,321 drug-tolerant controls from epilepsy cohorts of northern European and Han Chinese descent. Results from each cohort were meta-analyzed. RESULTS: We report an association between a rare variant in the complement factor H-related 4 (CFHR4) gene and phenytoin-induced MPE in Europeans (p = 4.5 × 10-11; odds ratio [95% confidence interval] 7 [3.2-16]). This variant is in complete linkage disequilibrium with a missense variant (N1050Y) in the complement factor H (CFH) gene. In addition, our results reinforce the association between HLA-A*31:01 and carbamazepine hypersensitivity. We did not identify significant genetic associations with MPE among Han Chinese patients. CONCLUSIONS: The identification of genetic predictors of MPE in CFHR4 and CFH, members of the complement factor H-related protein family, suggest a new link between regulation of the complement system alternative pathway and phenytoin-induced hypersensitivity in European-ancestral patients.