Pearson syndrome, also known as Pearson marrow-pancreas syndrome, is a rare multisystem disease that typically presents in infancy. It is characterized by bone marrow failure, anemia, neutropenia, thrombocytopenia, vacuolation of the hematopoietic precursor cells, lactic acidosis, fibrosis, and pancreatic exocrine dysfunction, resulting in malabsorption and chronic diarrhea. Presence of vacuolization in granular and erythroblastic progenitors visible on myelogram is highly indicative of the syndrome.

Approximately one-half of patients will die in infancy or early childhood due to liver failure or severe lactic acidosis complications. Patients who survive into adulthood usually develop Kearns-Sayre syndrome.

Pearson syndrome is caused by single, large deletions in mitochondrial DNA.

There is no specific treatment. Early diagnosis and close monitoring to prevent possible complications are recommended.