A Case Series of Disproportionate Elevations of Cardiac Troponin and Macrotroponin in Fabry Disease

Fabry disease is a rare X-linked lysosomal storage disorder that causes progressive cellular accumulation of glycosphingolipids, leading to various end-organ manifestations such as chronic kidney disease and cardiomyopathy. Currently, troponin is the preferred biomarker to identify acute coronary syndromes and cardiac inflammation/myocarditis, as well as monitor myocardial damage. Macrotroponin is an immunoglobulin G-troponin bound complex with reduced clearance due to its higher molecular weight. This can cause false elevations in troponin, in the absence of myocardial damage, which has been reported in up to 5% of patients presenting to emergency departments in Australia. In this case series, we report on ten Fabry patients in whom macrotroponin was demonstrated after precipitation with polyethylene glycol (PEG). Of the 47 routine clinical samples of Fabry patients that were analysed, troponin was demonstrated to be elevated in 15 samples (32%), and ten of these demonstrated macrotroponin (21% of total, 67% of elevated troponin). This case series highlights the need to consider the possibility of macrotroponin in Fabry patients with elevated troponin. This relatively high prevalence raises the questions of whether Fabry patients are intrinsically more predisposed to macrotroponin and how this influences clinical management, which warrants further research.