Clinical Characteristics

Clinical presentation of the patients with mitochondrial complex I deficiency typically include:
•    neurological problems, such as abnormal brain function (encephalopathy), recurrent seizures (epilepsy), intellectual disability, difficulty coordinating movements (ataxia), or involuntary movements (dystonia), white matter abnormalities consistent with Leigh syndrome seen on brain imaging
•    low muscle tone (hypotonia), muscle pain (myalgia), and extreme fatigue in response to physical activity (exercise intolerance).
•    elevated levels of lactic acid in the blood which can cause nausea, vomiting, weakness, and rapid breathing.