Pearson syndrome is a rare, sporadic multiorgan disorder that continues to evolve. It is caused by a deletion in the Mitochondrial DNA (mtDNA). Single large-scale Mitochondrial DNA (mtDNA) deletion syndromes (SLSMDS) include three syndromes with overlapping phenotypes: 1. Pearson Syndrome (PS), 2. Kearns-Sayre syndrome (KSS), 3. Chronic Progressive External Ophthalmoplegia (CPEO). PS is characterized by three cardinal clinical features: macrocytic sideroblastic anemia, exocrine pancreatic insufficiency, and lactic acidosis. We report a new patient with Pearson Syndrome with a unique clinical presentation. Fanconi syndrome, adrenal insufficiency, and hypoglycemia were some of our patient’s clinical manifestations suggestive of “Pearson like” phenotype. This case report aims to focus on the large still expanding clinical spectrum of PS overtime. This phenomenon is due to heteroplasmy; i.e. coexistence of copies of Mutated DNA (Δ-mtDNA) in the same cell with Wild-Type DNA (wtDNA). As proven by our patient’s case, whole-exome sequencing of blood, testing both mitochondrial and nuclear DNA led to the diagnosis.