Neonatal tyrosyluria

Neonatal tyrosyluria is corrected by one large (50-100 mg) dose of ascorbic acid and may be attributed to delayed maturation of hepatic ascorbate-dependent 4-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27)... 

The unusual sulphur containing amino acid, hawkinsin , and cis- and transA-hydroxycyclohexylacetic acid observed in an extensively reported patient with transient neonatal tyrosinaemia (Danks et al., 1975 Niederwieser et al., 1977) in whom a defect in 4-hydroxyphenylpyruvate oxidase (see below) had been postulated (Niederwieser et al., 1978) have not been observed in any other patients with tyrosyluria or tyrosinaemia. The origins of these metabolites and their quantitative significance remain questionable, but it is perhaps significant that Bindel et al. (1976) have found 4-hydroxycyclo-hexane-l-carboxylic acid in the urine of several children with suspected metabolic disorders and proposed a dietary source for the metabolite. A bacterial origin also appears possible. 

---