title: Azathioprine myelosuppression in multiple sclerosis: characterizing thiopurine methyltransferase polymorphisms.
abstract: We describe two multiple sclerosis patients who developed pancytopenia following treatment with azathioprine. They were found to have the homozygous polymorphism for thiopurine methyltransferase deficiency and recovered after cessation of drug therapy. We review the literature concerning this molecular derangement and underscore the importance of performing surveillance testing for allelic characterization prior to treatment intervention with this agent for immune-mediated disorders.
authors.affiliation: Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235, USA. elliot.frohman@utsouthwestern.edu
authors.forename: E M
authors.initials: EM
authors.lastname: Frohman
authors.forename: E
authors.initials: E
authors.lastname: Havrdova
authors.forename: B
authors.initials: B
authors.lastname: Levinson
authors.forename: O
authors.initials: O
authors.lastname: Slanar
mesh_terms: D000293:Adolescent; D001379:Azathioprine / Q000009:adverse effects*; D005260:Female; D014644:Genetic Variation; D006720:Homozygote; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D008780:Methyltransferases / Q000235:genetics*; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics*; D010198:Pancytopenia / Q000139:chemically induced*; D011110:Polymorphism, Genetic
chemical_list: D007166:Immunosuppressive Agents; D008780:Methyltransferases; C022745:thiopurine methyltransferase; D001379:Azathioprine