A paediatric case of macro aspartate aminotransferase

Macroenzymes are enzymes in plasma that have a higher molecular mass than the corresponding enzyme normally present under (patho) physiological conditions. Macro species have been described for most routinely measured enzymes, but with only a few reports of macro species with aspartate aminotransferase (AST), and in particular very few reports in children and adolescents. Routine biochemical analysis in a 15-year-old girl presenting with lower back pain revealed an isolated raised AST as part of a liver function test profile. Polyethylene glycol precipitation and gel filtration chromatography showed this to be a macro species.