TYMP and mitochondrial neurogastrointestinal encephalomyopathy: Mitochondrial neurogastrointestinal encephalomyopathy, the prototype of mitochondrial IF with pseudo-obstruction, is a rare autosomal recessive disease due to defects in the thymidine phosphorylase gene, encoding the enzyme responsible for the conversion of deoxynucleosides (deoxythymidine and deoxyuridine) [127].