The MNGIE type MTDPS1 (henceforth called “MNGIE”) (OMIM #603041) is caused by mutations in the TYMP gene located on chromosome 22q13.33, which results in the accumulation of the thymidine (dThd) and deoxyuridine (dUrd) substrates, nucleotide pool imbalance, and mtDNA instability with impairment of the mitochondrial genome replication and depletion, multiple deletions, and point mutations [4,5,6]. This evidence concerns the gene TYMP and mitochondrial neurogastrointestinal encephalomyopathy.