Tyrosinemia type I -: clinical and biochemical symptoms of three infants

Background. Tyrosinemia type I is an autosomal recessively inherited deficiency of fumarylacetoacetate hydrolase resulting in accumulation of tyrosin and its degradation products (succinylacetoacetone mainly). Typical clinical features include liver and kidney failure as well as central nervous system involvement. There are three main forms of the disease: the acute form with manifestation in newborn infants and the subacute and the chronic form in children older than one year of age. Case reports. We report on three infants with acute tyrosinemia type I. In two patients impaired liver function with coagulopathy, hypalbuminemia and low cholinesterase as well as renal tubulopathy with urinary phosphate loss led to the diagnosis. In one patient high galactose and phenylalanine levels at routine neonatal screening gave the hint for further investigations. All patients had anemia and thrombocytopenia. Diagnosis was established by measurement of urinary succinylacetoacetone at mean age of 54.6 days. Treatment. Treatment with 2-(nitro-4-trifluoromethylbenzoyl)-1-3-cyclohexanedione (NTBC) and a diet low in tyrosine,and phenylalanine was started. Clinical improvement and normalization of laboratory findings were noted in all patients. Discussion. Tyrosinemia type 1 must be considered in newborns and infants with impaired hepatic synthesis of coagulation parameters,albumin and cholinesterase and with additional signs of renal tubulopathy (hypophosphatemia and rickets mainly). For diagnosis measurements of urinary succinylacetoacetone is essential.