Phospholipid storage in the myocardium of a unique Japanese case of idiopathic cardiomyopathy

BackgroundA unique adult male patient who developed cardiomyopathy was first suspected to have cardiac Fabry disease based on the pathological findings in heart tissues obtained on biopsy, but the α-galactosidase activity in his leukocytes was normal and no mutation was detected in the coding region of the α-galactosidase gene. We identified accumulated materials in the myocardium of this patient.MethodsPathological and biochemical analyses were performed using the autopsied heart tissues as samples.ResultsAlthough numerous lamellar and concentric inclusion bodies were ultrastructurally found in the autopsied myocardium, the α-galactosidase activity in the heart tissues was not decreased. Lipid analysis revealed the accumulation of phospholipids including phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol, but not globotriaosylcereamide or gangliosides.ConclusionsWe found that a large amount of phospholipids accumulated in the myocardium of a patient with idiopathic cardiomyopathy, and electron microscopic findings of lamellar and concentric inclusion bodies in cardiomyocytes. A cardiac phospholipid storage disorder should be considered as an important candidate disease on differential diagnosis of myocardiac disorders including cardiac Fabry disease.