Tyrosinemia is a term encompassing three disorders in which genetic mutations lead to various enzyme deficiencies and subsequent accumulation of tyrosine in organs and tissues. Type I is by far the most common, characterized by a severe, early-onset presentation of renal and liver failure that is frequently fatal in the first decade. Early recognition and proper treatment may significantly increase life-expectancy, but in order to make the diagnosis, a thorough clinical and biochemical workup is critical.
Tyrosinemia is a clinical entity describing abnormally high circulating concentrations of the amino acid tyrosine and may be seen due to various genetic mutations. Three distinct types of tyrosinemia are recognized       :
Because of the rare occurrence of tyrosinemia in clinical practice, the diagnosis might be difficult to attain. For this reason, the role of a detailed patient history and a proper physical examination are crucial in order to raise suspicion. The physician should obtain all information regarding the onset of symptoms, their progression, as well as severity and duration, either from the patient or from the parents (given the early onset of tyrosinemia type 1). The fact that autosomal recessive patterns of inheritance are confirmed for all tyrosinemias   , a family history (although not always informative) can provide vital clues into the etiology. The cornerstone of diagnosis, however, rests on the assessment of tyrosine and its metabolites (mainly succinylacetone) in blood and urine, which should be ordered as soon as sufficient evidence is gathered  . As a definitive diagnostic method, genetic studies, such as mutational analysis, can be used both prenatally and postnatally  .