What causes Gyrate Atrophy?
Gyrate Atrophy arises because of mutations in the OAT gene located on chromosome 10. When working normally, the OAT gene codes for the enzyme ornithine aminotransferase. This enzyme is active in the mitochondria and helps process excess nitrogen that is generated by protein breakdown. A deficiency in ornithine aminotransferase causes plasma ornithine levels to rise tenfold, which is toxic to the retinal pigment epithelium (RPE) and choroid1.
Gyrate Atrophy follows an autosomal recessive pattern of inheritance and only affects individuals who have two copies of the mutated OAT gene, one from each parent. People with only one mutated gene copy are known as “carriers” and are not affected by the condition but may pass the faulty gene copy to their children.
Genetic testing can help to identify mutations in the OAT gene and confirm a diagnosis of Gyrate Atrophy, while some newborn screening procedures also test for gyrate atrophy.