Dietary management practices in phenylketonuria: results of an Italian multicentric survey and comparison with the European guidelines

– Objective: Phenilalanine (Phe)-restricted diet is the cornerstone of treatment of phenylketonuria (PKU). Dietary management remains heterogeneous in Europe despite the publication of the PKU European Guidelines (EG) in 2017. We conducted a multicentric survey on PKU dietary management in Italy to investigate the current situation. Materials and methods: From February to March 2023, a survey on PKU dietary management in Italy was con- ducted after the publication of the PKU EG. The survey, encompassing the timing of initiation of therapy, ideal Phe concentration, protein requirements, dietary Phe management, and use of protein substitutes, was administered to Italian metabolic dietitians from 13 clinical centers.Results: The survey showed that 61% of dietitians changed their practice after the publication of EG. In particular dietary approach was simplified, allowing free intake of food with phe <75 mg/100 g. Moreover, according to EG, dietary treatment was anticipated within 10 days of life in 85% of cases. The target Phe concentration was in line with EG, while the EG range in pregnancy (120–360 μmol/l) was achieved in 54% of cases. Regarding the total protein prescriptions, dietitians suggested the appropriate for general population or a 20–40% increase in 23% and 67%, respectively. All centers prescribed glycomacropeptide-containing substitutes, including in PKU pregnancies (54%). Large-neutral amino acids were used in 61% of centers. In sports activities, 77% of centers reported specific adapta- tions. During intercurrent illnesses, 61% of centers reduced or discontinued natural protein intake. Conclusions: This study adds new insights into dietary management of PKU in Italy, fostering shared manage- ment for treatment personalization in PKU.