Richner-Hanhart, also known as tyrosinemia type 2, is an autosomal recessive disease of tyrosine metabolism. Males and females are equally affected. The first observed manifestation is often keratitis presenting in the first several years of life. This can progress to ulceration, bilateral pseudodendritic keratitis, or blindness. Classic plantar keratoderma is preceded by bullae, erosions, or erythema. Keratoderma is focal and shows a predilection to weight-bearing surfaces of the feet. Affected children can show delay or refusal to walk secondary to pain.

Intellectual disability in these patients is highly variable in severity. Many of the cutaneous manifestations can improve with dietary restrictions, and, thus, early diagnosis and intervention is paramount. Such restrictions, however, have not been shown to reverse intellectual disability. These patients have a normal lifespan.