Phenylketonuria (PKU) is a rare inherited disease that affects the breakdown of the amino acid phenylalanine in the body. Without treatment, PKU can lead to severe mental impairment. Early treatment with a low-protein diet can prevent brain damage, but subtle changes in cognition, brain structure and function can still occur. Long-term effects of PKU on the ageing process of the brain remain largely unexplored. 

In the PICO-5 study, we examine the brain ageing process in 30 patients compared to 30 controls over 5 years. The baseline examination has already taken place between 2019 and 2022 and included an MRI of the brain, a neuropsychological assessment and blood analyses. We are now planning a follow-up measurement with the same examinations as the baseline in order to record changes in cognition and brain structure. 

The focus of the PICO-5 longitudinal trial is on determining the "brain age", a metric for the structural state of the brain relative to age. The aim is to gain insights into the long-term effects of PKU on brain structure and ageing and to improve future treatments.