TYMP and mitochondrial neurogastrointestinal encephalomyopathy: Recessive TYMP variants classically cause a progressive and multisystemic syndrome with potentially fatal gastrointestinal dysmotility and cachexia, combined with myopathy and neuropathy, named mitochondrial neurogastrointestinal encephalopathy (MNGIE), with both depletion and multiple mtDNA deletions having been described [270–272].