Overview of European Practices for Management of Tyrosinemia Type 1: Towards European Guidelines.

The introduction of nitisinone (NTBC) and newborn screening for Tyrosinemia type 1 (TT1) enabled preemptive treatment of patients, thereby significantly improving outcomes by preventing liver, kidney, and neurological issues. Treatment goals have shifted from emergency treatment to long-term care. To evaluate the risk of developing complications with aging, due to TT1 itself or its treatment, long-term follow-up is essential. In 2014, an overview of TT1 management practices in Europe was published. Within the Metabolic European Reference Network's subnetwork on amino-and-organic acidurias (MetabERN-AOA), we considered it important to give an update on current TT1 management practices in Europe. An online survey study was performed among members of the MetabERN-AOA subnetwork, and participants of a workshop on TT1 at the European Metabolic Group Meeting of Nutricia. Findings were compared to existing data from the aforementioned publication from 2014 and previously published recommendations. Thirty-two centers (16 European countries) completed the survey. Both consistencies and inconsistencies in TT1 management were seen. Inconsistencies were observed in the frequency and methods of follow-up, dosing of NTBC, and target ranges of biochemical markers. Compared to 2014, key differences included an increased number of patients detected by newborn screening, lower NTBC dosing, and a shift from interest in mainly hepatic to hepatic and neurocognitive outcomes. These results align with trends seen in TT1 recommendations over the years. In addition to numerous consistencies, many aspects in TT1 management still differ widely across Europe, suggesting the need for uniform guidance in clinical management beyond existing recommendations.