A Tunisian patient with Pearson syndrome harboring the 4.977kb common deletion associated to two novel large-scale mitochondrial deletions

► We reported a Tunisian patient with clinical features of Pearson syndrome. ► The detected common 4.977kb mitochondrial deletion (nt 8483–13459). ► Long-range PCR amplification revealed the presence of two novel mitochondrial deletions. ► The 5.030kb deletion (8131–13160) was located in 11bp imperfect direct repeats ► The 5.234kb deletion (8051–13284) was flanked by 12bp imperfect direct repeats. Pearson syndrome (PS) is a multisystem disease including refractory anemia, vacuolization of marrow precursors and pancreatic fibrosis. The disease starts during infancy and affects various tissues and organs, and most affected children die before the age of 3years. Pearson syndrome is caused by de novo large-scale deletions or, more rarely, duplications in the mitochondrial genome. In the present report, we described a Pearson syndrome patient harboring multiple mitochondrial deletions which is, in our knowledge, the first case described and studied in Tunisia. In fact, we reported the common 4.977kb deletion and two novel heteroplasmic deletions (5.030 and 5.234kb) of the mtDNA. These deletions affect several protein-coding and tRNAs genes and could strongly lead to defects in mitochondrial polypeptides synthesis, and impair oxidative phosphorylation and energy metabolism in the respiratory chain in the studied patient.