Tyrosinemia is an aminoacidopathy of tyrosine metabolism with elevated serum and urinary tyrosine excretion and related metabolites. Type I results in inhibition of some renal tubular function. The renal implications are similar to the renal dysfunction observed with Fanconi syndrome (see p. 132). Tyrosinemia is also known as hereditary tyrosinemia type I (HTI).

The overall incidence of tyrosinemia is estimated at 1:100,000. Northern European populations demonstrate an approximate incidence of 1:8000, whereas the population of Quebec, Canada, demonstrates an incidence of 1:1846. There is no gender preference.

HTI results from the homozygous, autosomal recessive inheritance of a genetic mutation on chromosome 15, loci q23-q25. To date 30 distinct mutations at these loci have been documented.