title: Macro creatine kinase types 1 and 2: clinical significance in neonates and children as compared with adults.
abstract: We examined the case histories of seven pediatric patients (ages four days to 12 years) whose sera showed significant activities of "macro" creatine kinase (CK; EC 2.7.3.2): two cases of macro CK type 1 (CK-BB isoenzyme bound to IgG) and five cases of macro CK type 2 (polymeric complexes of mitochondrial CK). The diagnoses of the two children with macro CK type 1 were similar to those in 55 adult patients with this form of CK found earlier during screening of a population of 5000. Macro CK type 1 has generally been noted only in older women; this is the first report of it in children. In four of the five cases of macro CK type 2 we found in children, myocardial muscle damage was clinically evident. In contrast, the 26 cases of adults with macro CK type 2 found during the same screening generally had neoplasms, most with metastases to the liver. We suggest that the finding of macro CK type 2 is an indicator of cellular necrosis; in pediatric cases with myocardial damage the associated conditions may be reversible but in adults with malignancies the finding is associated with an extremely poor prognosis.
mesh_terms: D000293:Adolescent; D009202:Cardiomyopathies / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006333:Heart Failure / Q000097:blood; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007527:Isoenzymes; D008113:Liver Neoplasms / Q000097:blood / Q000556:secondary; D008297:Male; D011379:Prognosis
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase