Ornithine aminotransferase deficiency

Ornithine aminotransferase deficiency (also known as gyrate atrophy of the choroid and retina) is an inborn error of ornithine metabolism, caused by decreased activity of the enzyme ornithine aminotransferase. Biochemically, it can be detected by elevated levels of ornithine in the blood. Clinically, it presents initially with poor night vision, which slowly progresses to total blindness. It is believed to be inherited in an autosomal recessive manner. Approximately 200 known cases have been reported in the literature. The incidence is highest in Finland, estimated at 1:50,000.

Research suggests there can be some adverse effect on muscles and also the brain. The cause of this is somewhat unclear but may relate to very low levels of creatine often found in this population.

Treatment may include vitamin B6, lysine or dramatic dietary change to minimise arginine from patients diet. Research has indicated that these treatments may be somewhat effective in lowering ornithine blood concentration levels in some patients, either in combination or individually. Vitamin B6 has been found to be very effective in a small proportion of patients.