title: Genetic variants associated with antithyroid drug-induced agranulocytosis: a genome-wide association study in a European population.
abstract: Drug-induced agranulocytosis is a potentially life-threatening adverse reaction. Genome-wide association studies (GWASs) in ethnic Chinese people in Taiwan and Hong Kong have shown an association between agranulocytosis induced by antithyroid drugs and the HLA alleles HLA-B*38:02 and HLA-DRB1*08:03. We aimed to identify genetic variants associated with antithyroid drug-induced agranulocytosis in a white European population.
  
  
  
  We did a GWAS in 234 European adults with any non-chemotherapy drug-induced agranulocytosis (absolute neutrophil count ≤0·5 × 10(9)/L [≤500/μL]) and 5170 population controls. 39 of the 234 patients had agranulocytosis that was induced by antithyroid drugs (thiamazole [methimazole], carbimazole, or propylthiouracil). After imputation and HLA allele prediction, 9 380 034 single nucleotide polymorphisms (SNPs) and 180 HLA alleles were tested for association. The genome-wide significance threshold was p<5 × 10(-8).
  
  
  
  Agranulocytosis induced by non-chemotherapy drugs in general was significantly associated with the HLA region on chromosome 6, with odds ratios (ORs) of 3·24 (95% CI 2·31-4·55, p=1·20 × 10(-11)) for HLA-B*27:05 and 3·57 (2·61-4·90, p=2·32 × 10(-15)) for the top SNP (rs114291795). Drug-specific analysis showed that the association with HLA-B*27:05 was largely driven by cases induced by antithyroid drugs. In a multiple logistic regression model, the OR for HLA-B*27:05 was 7·30 (3·81-13·96) when antithyroid drug-induced agranulocytosis was compared with population controls (p=1·91 × 10(-9)) and 16·91 (3·44-83·17) when compared with a small group of hyperthyroid controls (p=5·04 × 10(-4)). Three SNPs were strongly associated with antithyroid drug-induced agranulocytosis: rs652888 (OR 4·73, 95% CI 3·00-7·44, p=1·92 × 10(-11)) and rs199564443 (17·42, 7·38-41·12, p=7·04 × 10(-11)), which were independent of HLA-B*27:05, and rs1071816 (5·27, 3·06-9·10, p=2·35 × 10(-9)) which was in moderate linkage disequilibrium with HLA-B*27:05. In heterozygous carriers of all three SNPs, the predicted probability of antithyroid drug-induced agranulocytosis was about 30% (OR 753, 95% CI 105-6812). To avoid one case of agranulocytosis, based on the possible risk reduction if all three SNPs are genotyped and carriers are treated or monitored differently from non-carriers, roughly 238 patients would need to be genotyped.
  
  
  
  In white European people, antithyroid drug-induced agranulocytosis was associated with HLA-B*27:05 and with other SNPs on chromosome 6. In the future, carriers of these variants could be placed under intensified monitoring or offered alternative treatment for hyperthyroidism.
  
  
  
  Swedish Research Council, Swedish Heart and Lung Foundation, Clinical Research Support at Uppsala University, German Federal Institute for Drugs and Medical Devices, Carlos III Spanish Health Institute, European Regional Development Fund, UK National Institute for Health Research, The Selander's Foundation, Thuréus Foundation, European Commission, and Science for Life Laboratory.
authors.affiliation: Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Pär
authors.initials: P
authors.lastname: Hallberg
authors.affiliation: Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden; Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Eriksson
authors.affiliation: Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Fundació Institut Català de Farmacologia, Barcelona, Spain.
authors.forename: Luisa
authors.initials: L
authors.lastname: Ibañez
authors.affiliation: Service de Pharmacologie Médicale et Clinique, Centre Hospitalier Universitaire, Faculté de Médecine de l'Université de Toulouse, Toulouse, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Bondon-Guitton
authors.affiliation: Institut für Klinische Pharmakologie und Toxikologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Kreutz
authors.affiliation: Centro de Estudios sobre la Seguridad de los Medicamentos, Universidad de Valladolid, Valladolid, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Carvajal
authors.affiliation: S Farmacologia Clinica, Instituto de Investigación Biomédica de Málaga, Hospital Universitario Virgen de la Victoria, Universidad de Málaga, Málaga, Spain; Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Madrid, Spain.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Lucena
authors.affiliation: Servei d'Hematologia i Banc de Sang, Hospital General de Catalunya, Sant Cugat del Vallès, Spain.
authors.forename: Esther Sancho
authors.initials: ES
authors.lastname: Ponce
authors.affiliation: Department of Primary Care and Public Health Sciences, National Institute for Health Research Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Mariam
authors.initials: M
authors.lastname: Molokhia
authors.affiliation: Instituto de Parasitologia y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Granada, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Martin
authors.affiliation: Department of Medical Sciences, Molecular Medicine and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Axelsson
authors.affiliation: Medical Products Agency, Uppsala, Sweden.
authors.forename: Qun-Ying
authors.initials: QY
authors.lastname: Yue
authors.affiliation: Swedish Twin Registry, Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
authors.forename: Patrik K E
authors.initials: PK
authors.lastname: Magnusson
authors.affiliation: Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden. Electronic address: mia.wadelius@medsci.uu.se.
authors.forename: Mia
authors.initials: M
authors.lastname: Wadelius
mesh_terms: D000328:Adult; D000368:Aged; D000380:Agranulocytosis / Q000139:chemically induced / Q000235:genetics*; D013956:Antithyroid Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D002896:Chromosomes, Human, Pair 6; D005260:Female; D055106:Genome-Wide Association Study; D015796:HLA-B27 Antigen / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D044465:White People / Q000235:genetics; D055815:Young Adult
chemical_list: D013956:Antithyroid Agents; C464936:HLA-B*27:05 antigen; D015796:HLA-B27 Antigen