Nitisinone treatment during two pregnancies and breastfeeding in a woman with tyrosinemia type 1 - a case report.

OBJECTIVES: Tyrosinaemia type 1, an inherited disorder of tyrosine metabolism, is usually treated with a tyrosine-defined diet and since 2000 with nitisinone. So far, data about effects of nitisone during pregnancy and breastfeeding are rare. This is the first report of two pregnancies in a patient with tyrosinaemia type 1 while under treatment with nitisinone. CASE PRESENTATION: We here present a 20-year-old female patient with tyrisonemia type 1 receiving treatment with nitisinone and a tyrosine-defined diet since she was diagnosed with tyrosinaemia type 1 at the age of 18 months. During two pregnancies blood concentrations of tyrosine, succinylacetone and nitisinone were measured regularly. Neither infant has tyrosinaemia type 1 and both showed an initial increase in concentrations of tyrosine, succinylacetone and nitisinone. All three metabolites dropped within two weeks after birth. Both were exclusively breastfed for about two weeks. Both children show age-appropriate physical and mental development. CONCLUSIONS: Nitisinone therapy during pregnancy and the short breastfeeding period did not result in adverse events in our patient or her children. Regular assessments of tyrosine, succinylacetone and nitisinone should be made during pregnancy and the breastfeeding period in both the mother and the infant. For better understanding, in principle, all cases of pregnancy and breastfeeding with tyrosinemia type 1 should be assessed and followed to further evaluate the implications of tyrosinaemia type 1 and its treatment during pregnancy. Additionally, even though experience with breastfeeding is limited, medication with nitisinone is safe and there is no reason to consider breastfeeding unsafe or to not recommend it.

Hepatorenal Tyrosinaemia: Impact of a Simplified Diet on Metabolic Control and Clinical Outcome.

Background: Tyrosinaemia type 1 is a rare inherited metabolic disease caused by an enzyme defect in the tyrosine degradation pathway. It is treated using nitisinone and a low-protein diet. In a workshop in 2013, a group of nutritional specialists from Germany, Switzerland and Austria agreed to advocate a simplified low-protein diet and to allow more natural protein intake in patients with tyrosinaemia type 1. This retrospective study evaluates the recommendations made at different treatment centers and their impact on clinical symptoms and metabolic control. Methods: For this multicenter study, questionnaires were sent to nine participating treatment centers to collect data on the general therapeutic approach and data of 47 individual patients treated by those centers. Results: Dietary simplification allocating food to 3 categories led to increased tyrosine and phenylalanine blood concentrations without weighing food. Phenylalanine levels were significantly higher in comparison to a strict dietary regimen whereas tyrosine levels in plasma did not change. Non-inferiority was shown for the simplification and liberalization of the diet. Compliance with dietary recommendations was higher using the simplified diet in comparison to the stricter approach. Age correlates negatively with compliance. Conclusions: Simplification of the diet with increased natural protein intake based on three categories of food may be implemented in the diet of patients with tyrosinaemia type 1 without significantly altering metabolic control. Patient compliance is strongly influencing tyrosine blood concentrations. A subsequent prospective study with a larger sample size is necessary to get a better insight into the effect of dietary recommendations on metabolic control.