Background: Prior to 2018, sapropterin hydrochloride (BH4, Kuvan®) had not been used in Queensland, Australia, to treat sapropterin-responsive phenylketonuria (PKU). This gave our centre at the Queensland Children’s Hospital the opportunity to assess the difference a new treatment makes to the quality of life of the child and family.

Study design and methods: A qualitative study design was used. Forty parents of children with a sapropterin-responsive form of PKU (one parent per family) were invited to take part in a semi-structured one-on-one interview exploring their experiences and perspectives on commencing sapropterin therapy with their child. Thirty-eight parents met the eligibility criteria, 23 consented to participate, and 21 were able to be contacted for an interview. Data collected included family background and their experiences pre and post commencement of sapropterin therapy and its impact on their child(ren), diet, and physical and psychosocial wellbeing.

Results: Four key themes emerged from thematic analysis: a) psychosocial wellbeing, b) child health and nutrition, c) family economic benefits, and d) parent-child interactions. Overall, parents reported positive experiences and reduced impact of PKU on child, parent, and family quality of life following initiation of sapropterin therapy. The majority reported a sense of relief and optimism and expressed that they were able to manage their child’s PKU more effectively than before.

Conclusions: Sapropterin therapy is associated with physical and psychosocial benefits for children and families, including improved psychosocial wellbeing, parent-child relationship quality, and child health and nutrition.

Implications for research, policy, and practice: Commencement of sapropterin therapy can result in physical and psychosocial benefits for children with phenylketonuria and their families. Longer-term follow-up studies are warranted.