Leigh's disease, also known as sub-acute necrotizing encephalopathy, is a rare progressive metabolic disorder affecting the central nervous system. This disorder is generally seen in infants, and rarely in teenagers and adults. The pathophysiology underlying the disease is a defect in cellular energy production, especially affecting the brain stem. In infants, the earliest sign of this disorder is poor sucking ability, loss of head control, loss of appetite, vomiting, continuous crying, and seizures. The disease progresses rapidly, and infants may also show generalized weakness and lactic acidosis. The latter can even lead to respiratory and renal malfunctioning. Leigh's disease is often associated with movement disorders, most commonly dystonia. Some patients may also show rigidity, tremors, chorea, hypokinesia, myoclonus, or tics. In adults, the sequels include kidney failure and cardiac abnormalities.
A confirmed diagnosis of Leigh's disease is made on the basis of clinical features, biochemical tests, and brain scans. The most common treatment is administration of thiamine. The lactic acidosis can be managed by treating with sodium bicarbonate or citrate. A high-fat low-carbohydrate diet may also help, especially in the case of the X-linked form of the disease. The prognosis for the disease is poor. Even with treatment, most affected infants do not survive past 3-years of age, succumbing to respiratory or cardiac failure. Those with milder forms of the disease may survive up to the teenage years. Worldwide, 1 in 40,000 neonates are born with this disease. However, certain populations, like the one in a particular region in Quebec, Canada, have much higher incidences at 1 in 2,000.