The effect of diet on the ophthalmological, clinical and biochemical aspects of Richner-Hanhart syndrome: a morphological ultrastructural study of the cornea and the conjunctiva.

Type II tyrosinemia (Richner-Hanhart syndrome) is a familial aminoacid disorder, clinically characterized by ocular changes (keratitis), palmo-plantar hyperkeratosis, no constant mental changes with mental deterioration, abnormal urinary excretion and high serum tyrosine level in consequence of the absence of tyrosine-aminotransferase. Almost 20 families have been described in the literature of which 50% are of Italian origin, suggesting that this disorder is particularly frequent in our country. We report a family with 2 affected members with typical clinical and biochemical findings (keratitis, palmo-plantar hyperkeratosis, abnormal urinary and serum tyrosine concentrations), not suffering from mental retardation. Clinical symptoms completely disappeared after the decrease of urinary and serum tyrosine levels following a tyrosine- and phenylalanine-free diet. These cases are compared with those reported in literature, and the usefulness of diet for the improvement of clinical and metabolic symptoms is discussed.