Background：This nuclear gene encodes a mitochondrial protein tyrosine aminotransferase which is present in the liver and catalyzes the conversion of L-tyrosine into p-hydroxyphenylpyruvate. Mutations in this gene cause tyrosinemia （type II, Richner-Hanhart syndrome）, a disorder accompanied by major skin and corneal lesions, with possible mental retardation. A regulator gene for tyrosine aminotransferase is X-linked.
