Clinical assessment of growth patterns, weight, and dietary management in children and adults with phenylketonuria - a retrospective study.

BACKGROUND: Phenylketonuria (PKU) is an inherited metabolic disorder where the body cannot break down phenylalanine (Phe), leading to its harmful accumulation if left untreated. Concerns have been raised about growth and risk of overweight in PKU patients, with conflicting research findings. This retrospective study aims to assess growth patterns and the prevalence of overweight and obesity in Danish children and adults with PKU by comparing them with Danish growth charts and prevalence rates. RESULTS: Data were collected from medical records of 291 Danish patients from the National PKU Clinic at Rigshospitalet in Copenhagen, including data on age, sex, PKU phenotype, Phe levels, and anthropometric measurements from their last clinic visit. Weight status for children was classified according to Danish guidelines, while World Health Organization criteria were used for adults. All data analyses were carried out separately for children and adults. A total of 291 PKU patients were included, 116 children and 175 adults. Children had normal growth patterns compared to Danish growth charts. The rates of overweight and obesity among children were 15% and 1%, respectively, while 32% of adults were overweight, and 28% were obese. Adults with classic PKU were significantly more obese and had higher BMI levels compared to other phenotypes. Additionally, a slight positive correlation was noted between high Phe levels and the risk of being overweight. CONCLUSIONS: Children with phenylketonuria following a restricted diet achieve normal growth. However, overweight and obesity rates rise with age, particularly in adults with the most severe phenotype, suggesting disease severity may influence weight gain. The potential link between high phenylalanine levels and overweight requires further investigation. These findings highlight the need for ongoing weight and metabolic monitoring, as well as strategies to support weight management in adults with phenylketonuria.