Healthcare services need to be restructured in Italy to better support adults with phenylketonuria (PKU), regardless of whether or not they follow strict diet regimens, a study suggests.

The study, “The PKU & ME study: A qualitative exploration, through co-creative sessions, of attitudes and experience of the disease among adults with phenylketonuria in Italy,” was published in the journal Molecular Genetics and Metabolism Reports.

PKU is estimated to affect 6 per 100,000 births worldwide. The disease is caused by insufficient activity of an enzyme called phenylalanine hydroxylase (PAH), an enzyme that’s needed to break down the amino acid phenylalanine. Amino acids are the building blocks of proteins.

In the absence of a functional enzyme, phenylalanine builds up to toxic levels in the brain and other organs, leading to intellectual disabilities and other neurological impairments.

Evidence suggests that PKU can be successfully managed if patients follow a lifelong phenylalanine-restricted diet, which does not allow foods high in protein, such as meat, fish, and dairy. Low protein foods such as fruits, vegetables, and some cereals are allowed in limited quantities.

However, diet adherence is often challenging for patients due to its highly restrictive nature that makes appropriate food sourcing and preparation difficult and time-consuming. For this reason, diet adherence tends to decrease progressively during life, particularly following adolescence.

To evaluate the diet experiences of patients, as well as their overall disease management, investigators in Italy asked 21 young adults with PKU to participate in daily sessions consisting of a series of co-creation exercises followed by a group discussion.

Two sessions were held — one for 12 patients who adhered to their strict diets and another for nine who were not following strict diets — with two moderators. Verbatim notes gathered during both sessions were analyzed using content analysis.

All participants except for three had full-time jobs.

Those in the adherent group had an overall positive mental attitude and were highly organized. They were aware of the consequences of not following their restrictive diet, saying it could influence their mood and relationship with others, which they valued highly. These aspects served as motivation to accept and follow their diets.

“When I don’t follow the diet I get stressed and drown and drag down my boyfriend who tries to help me but can’t and I feel sorry for him,” one of the participants said.

In contrast, those in the non-adherent group did not seem to fully accept their health condition and limitations. In general, they perceived PKU as being more dangerous for children than for adults.

Some also said that although they had high levels of phenylalanine, they did not feel compelled to follow a strict diet, because they did not experience any symptoms. Many claimed PKU felt like a personal burden that was difficult to explain to others and was a source of emotional distress.

“Nobody has heard of it, we always have to explain,” a participant said.

“People sometimes think we are just annoying vegans, but for us it is not a choice,” another patient added.

Patients from both groups expressed the desire to receive support from a specialized healthcare setting dedicated to adults with PKU. Non-adherent patients also mentioned the need for more information on appropriate foods, recipes, access to scientific research, and social interactions with other adults with PKU.