title: Macro creatine kinase type 1: a cause of spuriously elevated serum creatine kinase associated with leukoencephalopathy in a child.
abstract: Macro creatine kinase type 1 is a complex formed by the creatine kinase isoenzyme BB and monoclonal IgG and occurs in about 1% of patients studied. First identified as a cause of spurious elevation of the total serum creatine kinase in patients suspected of myocardial infarction, the test has been largely replaced by the measurement of troponin levels. We present a child with delayed milestones and persistently elevated total serum creatine kinase measurements (∼ 1000-4000 IU) normal electromyogram and brisk myotatic reflexes. Creatine kinase isoenzymes and brain imaging showed the presence of macro creatine kinase type 1 and extensive signal abnormality of the cerebral white matter. Macro creatine kinase type 1 has been associated with several conditions though it has not been described in association with leukoencephalopathy or in patients this young. Macro creatine kinase type 1 can be a cause of elevated total creatine kinase in patients without primary muscle disease. The significance of the relationship of the macro creatine kinase to the leukoencephalopathy in this patient is unknown.
authors.affiliation: Mayo Clinic, Rochester, MN, USA Bodensteiner.John@mayo.edu.
authors.forename: John B
authors.initials: JB
authors.lastname: Bodensteiner
mesh_terms: D001921:Brain / Q000473:pathology; D002675:Child, Preschool; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006801:Humans; D056784:Leukoencephalopathies / Q000097:blood* / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D018482:Muscle, Skeletal / Q000473:pathology; D066127:White Matter / Q000473:pathology
chemical_list: D003402:Creatine Kinase
keywords: creatine kinase; leukoencephalopathy; macro creatine kinase type 1; myopathy