Digestive Dysmotility in Mitochondrial Neurogastrointestinal Encephalomyopathy

Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is an ultra-rare mitochondrial disease caused by mutations of the gen that codifies the enzyme thymidine phosphorylase The genetic defect results in systemic accumulation of the nucleosides thymidine and deoxyuridine. Clinically MNGIE is characterized by a combination of gastrointestinal and neurological manifestations, including severe gastrointestinal dysmotility, cachexia, ptosis, external ophthalmoplegia and sensorimotor neuropathy. Gastrointestinal symptoms are the most frequent first manifestation of the disease, and include early satiety, nausea, dysphagia, postprandial emesis, abdominal pain, abdominal distention, and diarrhea. The disease is relentlessly progressive and the cause of death is primarily related to digestive dysmotility. However, the specific motor dysfunctions that produce the symptoms, i.e., the underlying mechanisms, remain uncertain, because so far, no studies on gastrointestinal motility in MNGIE have been published. The aims of this study were to identify the upper GI motor dysfunction in MNGIE patients, and to determine their relation to the clinical manifestations. Since the life-threatening consequences of the disease involve the upper gastrointestinal tract, all patients, after a thorough clinical and neurological evaluation, fulfilled a structured clinical questionnaire on digestive manifestations, and underwent state-of-the-art evaluation of the esophagus and the small bowel by high-resolution manometry (HRM), and gastric emptying by scintigraphy