Background: Phenylketonuria (PKU) is a rare metabolic disorder that leads to severe neurological abnormalities unless early treated with a strict phenylalanine (Phe)-restricted diet. The parents' involvement in PKU management is crucial and could lead to psychological distress; however, few studies have explored the parents' psychological wellbeing. The study aimed to: 1) evaluate the presence of psychological distress and impaired quality of life among parents of children with PKU, assessing the impact of the diagnosis and the impact of the treatment management; 2) explore the associations between parents' psychological outcomes and their children's blood-Phe levels.
Methods: One hundred thirty-eight parents of patients with PKU (who need a Phe-restricted diet) and with a mild form (mild hyperphenylalaninemia-MHP, with no diet indication) filled-out self-report psychological questionnaires; Phe-levels of children with PKU were retrieved.
Results: Parents of children with PKU did not report higher levels of psychological distress neither compared with the normative scores nor with parents of children with MHP. Optimal Phe-levels were associated with a higher number of parents' depressive complaints, with a lower tendency to express anger feelings, with a lower social functioning, and a higher mental health.
Conclusions: Parents of children with PKU showed a good psychological adaptation to their children's disease and treatment. Findings highlighted associations between parents' psychological wellbeing and their children's adherence to diet. Interestingly, an optimal adherence to the diet of their children was associated with parental low social functioning, a higher tendency to control the anger expression, and greater somatic depressive symptoms.