BioTyrosin - Biomarker for the Early Diagnosis and Monitoring in Tyrosinemia Type 1 - An International, Multicenter, Epidemiological Protocol

Hereditary Tyrosinemia type 1 (HT-1) is a rare genetic disorder in which the newborn child lacks the ability to break down the amino acid tyrosine. As a result of this deficiency, toxic sub-stances build up in the blood and can cause liver failure, kidney dysfunction and neurological problems. There are two different forms of the disease - acute and chronic. The acute form is most common.

Worldwide, Tyrosinemia type 1 affects about one newborn child in 100,000, although geo-graphical variation is seen.

Tyrosinemia type 1 is hereditary. The disorder is caused by a defect in the gene coding for the enzyme responsible for breaking down tyrosine. For a child to be affected by the disease, both parents have to carry a defective gene. The risk of being born with Tyrosinemia type 1, i.e. receiving both genes from the parents, is thus 25%.

Children with Tyrosinemia type 1 can display symptoms such as failure to gain weight and grow at the expected rate, diarrhea, vomiting, enlarged liver, liver failure, accumulation of fluid in the peritoneal cavity, kidney failure, softening of the bones (rickets) and liver tumors.

The acute form usually appears in the first few months of life. The child has a slow weight gain plus fever, diarrhea, blood in the feces and vomiting. The liver is enlarged and yellowing of the skin and the whites of the eyes (jaundice) with an increased tendency to bleed (particularly nosebleeds) may be evident. The spleen and abdomen can also be enlarged and the legs swollen. Without treatment, liver failure and clotting problems can arise.