Tyrosinemia type II in two cases previously reported as Richner-Hanhart syndrome

Two sibs with palmo-plantar keratosis and dendritic corneal opacities, previously described as suffering from Richner-Hanhart syndrome by other authors, about 25 years ago, showed increased plasma and urine tyrosine levels. Their neurological and mental features were within normal limits. A comprehensive review of the literature showed a total of 47 cases of fully documented tyrosinemia type II; 8 more patients also had the clinical features of the disease, but aminoacidemia had never been observed. The importance of early diagnosis is stressed, since a low tyrosine-phenylalanine diet dramatically improves the symptoms and may prevent mental retardation.