Tyrosinemia type II: A metabolic genetic disease due to deficiency of the enzyme tyrosine transaminase. The disease is characterized by the deposition of crystals of tyrosine in the skin and eyes. Thickened areas (keratoses) on the palms and soles become painful and ulcers develop in the cornea. There is often mental retardation in tyrosinemia type II. It is inherited in an autosomal recessive manner.