Pearson marrow-pancreas syndrome with worsening cardiac function caused by pleiotropic rearrangement of mitochondrial DNA

Pearson marrow-pancreas syndrome is a usually fatal disorder that involves the hematopoietic system, exocrine pancreas, liver, kidneys, and often presents clinically with failure to thrive. We report a 5-year-old patient who developed, in addition to the typical features of Pearson syndrome, worsening cardiac function, mainly affecting the left ventricle. The latter finding is particularly interesting because cardiac involvement has not yet been regarded as a major feature of Pearson syndrome. The diagnosis was proved by the finding of so far undescribed pleioplasmatic rearrangement of mitochondrial (mt)DNA (loss of 5,630 bp, 70% deleted and duplicated mtDNA) in blood cells. Our report demonstrates that patients with Pearson syndrome may also have impaired cardiac function. Thus, Pearson syndrome should be considered in the differential diagnosis of patients with left ventricular dysfunction of unknown origin and other clinical findings suggestive of a mitochondrial disease.