TYROSINEMIA TYPE-III - DIAGNOSIS AND 10-YEAR FOLLOW-UP

Tyrosinemia type III, caused by deficiency of 4-hydroxyphenylpyruvate dioxygenase, is a rare disorder of tyrosine catabolism. Primary 4-hydr oxyphenylpyruvate dioxygenase deficiency has been described in only th ree patients. The biochemical phenotype shows hypertyrosinemia and ele vated urinary excretion of 4-hydroxyphenyl derivatives. We report the clinical and biochemical findings and the results of long-term follow- up in a new patient with this disorder presenting with severe mental r etardation and neurological abnormalities. The clinical phenotype is c ompared with those reported in the three previously described patients .