If the deficiency is not complete, the prognosis is somewhat better and an affected child is expected to survive 6–7 years, and in rare cases, to their teenage years. Epidemiology
Leigh syndrome occurs in at least 1 of 40,000 live births, though certain populations have much higher rates. In the Saguenay-Lac-Saint-Jean region of central Quebec, Leigh syndrome occurs at a rate of 1 in 2000 newborns. History
Leigh syndrome was first described by Denis Leigh in 1951 and distinguished from similar Wernickes encephalopathy in 1954. In 1968, the diseases link with mitochondrial activity was first ascertained, though the mutations in cytochrome c oxidase and other electron transport chain proteins were not discovered until 1977. See also
Joseph Maraachli case
Neuropathy, ataxia, and retinitis pigmentosa

References
Further reading
GeneReviews/NCBI/NIH/UW entry on Mitochondrial DNA-Associated Leigh Syndrome and NARP
OMIM entries on Mitochondrial DNA-Associated Leigh Syndrome and NARP
Leigh syndrome; Subacute necrotizing encephalopathy; Leighs disease at NIHs Office of Rare Diseases
leighsdisease at NINDS
Maternally Inherited Leigh Syndrome at NIHs Office of Rare Diseases


== External links ==
Hypouricemia or hypouricaemia is a level of uric acid in blood serum that is below normal. In humans, the normal range of this blood component has a lower threshold set variously in the range of 2 mg/dL to 4 mg/dL, while the upper threshold is 530 μmol/L (6 mg/dL) for women and 619 μmol/L (7 mg/dL) for men. Hypouricemia usually is benign and sometimes is a sign of a medical condition. Presentation
Complications
Although normally benign, idiopathic renal hypouricemia may increase the risk of exercise-induced acute kidney failure. There is also evidence that hypouricemia can worsen conditions such as rheumatoid arthritis, especially when combined with low Vitamin C uptake, due to free radical damage. Causes
Hypouricemia is not a medical condition itself (i.e., it is benign), but it is a useful medical sign. Usually hypouricemia is due to drugs and toxic agents, sometimes it is due to diet or genetics, and rarely it is due to an underlying medical condition. When one of these causal medical conditions is present, hypouricemia is a common sign. Medication
The majority of drugs that contribute to hypouricemia are uricosurics (drugs that increase the excretion of uric acid from the blood into the urine). Others include drugs that reduce the production of uric acid:  xanthine oxidase inhibitors, urate oxidase (rasburicase), and sevelamer. Diet
Hypouricemia is common in vegetarians due to the low purine content of most vegetarian diets. Vegetarian diet has been found to result in mean serum uric acid values as low as 239 μ mol/L (2.7 mg/dL).