PKU: it’s not just a paediatric condition; the dietary management can also be stressful for adults

Phenylketonuria (PKU) is a rare genetic metabolic disorder that affects approximately one in every 10,000 newborns in Europe and places a heavy strain on the daily lives of patients – or their parents, in the case of children – from birth. It is caused by a deficiency of an enzyme, phenylalanine hydroxylase, which in turn prevents the body from properly metabolising phenylalanine, an essential amino acid found in the proteins of common foods such as meat, fish, eggs, dairy products, cereals, pulses and nuts. For this reason, those affected must follow an extremely strict and restrictive dietary regime for the rest of their lives in order to maintain their health.

Whilst compulsory newborn screening now ensures timely diagnosis and intervention, the need to maintain a dietary management programme remains essential: without constant monitoring, the build-up of phenylalanine can impair brain development, leading to severe and irreversible clinical symptoms in untreated children.

However, the consequences of failing to maintain adequate levels of phenylalanine in the blood do not affect only paediatric patients. Although it is often regarded in the public imagination as a purely paediatric condition, failure to maintain adequate phenylalanine levels in adulthood is closely linked to neurocognitive and mood disorders: 51 per cent of people with PKU report a significant impact on their social life, 44 per cent on friendships and romantic relationships, and 41 per cent report difficulties in their relationships. This is the picture that emerges from the Elma Research survey carried out as part of the project “Libertà PHEnomenale. Free to aspire, beyond the challenges of phenylketonuria’, promoted by BioMarin with the support of the main patient associations working in the field of inherited metabolic disorders.

Having PKU and not following the treatment regime can therefore have a significant impact on relationships and social life, as well as on the development of an adequate level of self-esteem and self-determination, particularly when the patient reaches adolescence. The need to plan every meal meticulously often results in psychological stress: eating out is a major challenge for 50 per cent of those surveyed, whilst simply sharing food is a source of anxiety for 43 per cent. It is no coincidence, therefore, that 80 per cent of people with PKU involved in the study report regularly suffering from anxiety, fatigue, mood swings and cognitive difficulties.

This clinical and social need has given rise to the “Libertà PHEnomenale” campaign, which focuses on the need to restore a sense of normality and independence to patients in their day-to-day lives and in planning simple activities such as travelling or eating out. At the heart of the initiative are video testimonials from patients and carers, contributions from healthcare professionals, and the “wish book”: a digital guide offering practical advice, expert opinions and space for reflection to help navigate the complexities of the condition.