SNP Shot: Genomic Insights

Mitochondrial neurogastrointestinal encephalopathy (MNGIE) is a disease impacting multiple organ systems, primarily the digestive and nervous systems. While the onset of MNGIE can range from infancy to adulthood, symptoms typically manifest before the age of 20. The health issues associated with MNGIE progressively worsen.

Digestive system abnormalities are a prevalent and significant hallmark of MNGIE. Nearly all individuals with MNGIE experience gastrointestinal dysmotility, a condition where the digestive system's muscles and nerves fail to properly propel food through the digestive tract. This results in a range of digestive issues, including premature satiety (feeling full after eating little), difficulty swallowing (dysphagia), nausea and vomiting after meals, recurring abdominal pain, diarrhea, and intestinal obstructions. These gastrointestinal complications contribute to severe weight loss and muscle wasting (cachexia).

MNGIE also involves nervous system abnormalities, although these are generally less severe than the digestive problems. Affected individuals commonly experience tingling, numbness, and weakness in their extremities (peripheral neuropathy), particularly in the hands and feet. Other possible neurological signs and symptoms include drooping eyelids (ptosis), weakness of the eye muscles (ophthalmoplegia), and hearing impairment. Leukoencephalopathy, characterized by the degradation of the brain's white matter, is a key feature of MNGIE. While these brain changes are detectable through magnetic resonance imaging (MRI), they often do not cause noticeable symptoms.

Inheritance:

MNGIE is inherited in an autosomal recessive manner. This means that both copies of the TYMP gene within each cell must carry mutations for the disease to develop. Individuals with autosomal recessive conditions inherit one mutated gene copy from each parent. The parents, who each carry only one copy of the mutated gene, typically do not exhibit any signs or symptoms of MNGIE.