Macrolipasemia variant of macroenzymes: An endocrine laboma.

Abstract

Macroenzymes, formed by polymerization of physiological enzymes with immunoglobulins, have slower renal clearance rates due to their higher molecular mass. They are usually incidentally detected, have no pathophysiological importance, and can potentially lead to over-treatment and iatrogenic morbidity. We present, possibly for the first time, a macro-lipasemia variant of macroenzyme, detected in a 14-year-old girl with type-1 diabetes admitted with severe hyperglycaemia and pain abdomen. Raised lipase levels (414 U/L), initially raised the suspicion of underlying pancreatitis, which was ruled out by the clinical symptoms and normal ultrasound and CT imaging of the pancreas. Upper gastrointestinal endoscopy revealed pangastritis, which could explain the mild upper abdominal pain in the child. She improved with proton pump inhibitor therapy and was discharged after 5 days of hospital admission after good glycaemic control using multiple subcutaneous injections of insulin. Post-polyethylene glycol (PEG) precipitation, the recovery of lipase activity in PEG treated serum sample was 30.6% (127 U/L), which confirmed the presence of macrolipase. An increased clinical suspicion and performing a cheap reliable test (PEG precipitation), whenever there is clinical biochemical discordance can help us in diagnosing more patients with macroenzymes and macrolipasemia.