Overview of European practices for management of tyrosinemia type 1

The introduction of nitisinone (NTBC) and newborn screening for Tyrosinemia type 1 (TT1) enabled preemptive treatment ofpatients, thereby significantly improving outcomes by preventing liver, kidney, and neurological issues. Treatment goals haveshifted from emergency treatment to long-term care. To evaluate the risk of developing complications with aging, due to TT1itself or its treatment, long-term follow-up is essential. In 2014, an overview of TT1 management practices in Europe was pub-lished. 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 per-formed among members of the MetabERN-AOA subnetwork, and participants of a workshop on TT1 at the European MetabolicGroup Meeting of Nutricia. Findings were compared to existing data from the aforementioned publication from 2014 and pre-viously published recommendations. Thirty-two centers (16 European countries) completed the survey. Both consistencies andinconsistencies in TT1 management were seen. Inconsistencies were observed in the frequency and methods of follow-up, dosingof NTBC, and target ranges of biochemical markers. Compared to 2014, key differences included an increased number of patientsdetected by newborn screening, lower NTBC dosing, and a shift from interest in mainly hepatic to hepatic and neurocognitiveoutcomes. 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 man-agement beyond existing recommendations.