Prof. Dr. Anita MacDonald, RD, PhD
Dietician, Birmingham Women and Children’s Hospital & Member of the Scientific Advisory Committee, E.S.PKU
Phenylketonuria (PKU) is a rare genetic disorder identified by newborn screening. It is caused by an enzyme deficiency leading to the abnormal build-up of phenylalanine (part of protein) in the body.
Inadequate treatment of PKU can cause intellectual disability with low IQ, behavioural problems, inattention, depression, and anxiety. In pregnant women with poorly controlled PKU, it may cause birth defects in their infants. There is no cure for PKU.
The drudgery of dietary treatment
In the UK, the only lifelong treatment offered in PKU is an extremely strict diet. Although effective, it is difficult to apply. It avoids almost all-natural sources of protein (including meat, fish, eggs, soya, cheese, bread, and pasta).
There are few suitable foods which can be eaten without limit; one large baked potato may provide the entire days’ supply of phenylalanine; even foods such as cauliflower and broccoli must be weighed. An unpleasant tasting synthetic/artificial protein supplement is taken 3 times daily and low protein bread and flour alternatives provide energy. Dietary treatment is complex and relentless, requiring constant vigilance; it is a major cause of stress and guilt.
Drug companies have a responsibility to ensure that pioneering treatments are safe and affordable; whereas governments and health services should guarantee that approval processes are equitable, transparent, and streamlined.
Understandably, many find it difficult to continue this burdensome treatment. A child’s outcome will depend upon their parent’s ability to manage this therapy. Teenagers are commonly hungry and feel socially excluded from activities involving food; they require extraordinary levels of self-control. Parents and adult patients may need to reduce their working hours so they can manage treatment.
People with social vulnerabilities such as poor literacy, low incomes, lone parents, and living in poverty are particularly at risk. They may experience much red tape and barriers to accessing services and prescribed dietary treatment. They face daily prejudices and stigma about their restrictions.
The need for change
There is a long unmet need for new treatments in PKU. One such treatment, that has been licenced since 2008, helps up to 30% of patients but is unavailable in the UK. Many other new treatments are in the pipeline which could transform the lives of people with PKU. Across Europe, there should be collaboration amongst policy makers. They should agree standards and provide equal access to innovative treatments once they are licenced.
Drug companies have a responsibility to ensure that pioneering treatments are safe and affordable; whereas governments and health services should guarantee that approval processes are equitable, transparent, and streamlined. Drug cost and efficacy should be judged in a comparable way for all rare disorders across borders.
People of all ages with PKU deserve the right to choose alternative treatments if they are accessible within Europe. It is time to remove the injustice of treatment availability.