Synonyms: Richner-Hanhart syndrome (RHS), oculocutaneous tyrosinemia
Gene affected: TAT (tyrosine aminotransferase), in the liver
Gene locus: 16q22
Inheritance: autosomal recessive
Clinical features:
(1) mental retardation
(2) hyperkeratosis of the volar aspects of the hands and feet (keratosis palmaris et plantaris, palma-plantar keratoderma)
(3) thickening of the conjunctival epithelium
(4) corneal opacities (dendritic pseudokeratitis)
(5) photophobia
(6) frequent tearing
Onset is during infancy or early childhood.
Laboratory findings:
(1) increased plasma levels of tyrosine and tyrosine metabolites
(2) increased urine levels of tyrosine and tyrosine metabolites
Management includes a diet low in phenylalanine and tyrosine.
