Phenylketonuria (PKU) transitions in the teenage years

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Teenagers with phenylketonuria (PKU) face the unique challenge of balancing their health with their growing independence. Read about how you can support your teen with PKU.

Key points

  • As your teen grows older, they should become more confident and independent. They should be able to take on more responsibility.
  • Encourage your teen to take charge of their own health and life, and to solve problems for themselves.
  • Let your teen know that you are still there to help and support them.

What is phenylketonuria (PKU)?

Phenylketonuria (PKU) is an absence or deficiency in phenylalanine hydroxylase (PAH), an enzyme involved in metabolizing or converting the amino acid phenylalanine into tyrosine, another amino acid. PAH deficiency results in high levels of blood phenylalanine and an accumulation of phenylketones in the urine.

Partial deficiency of the enzyme results in hyperphenylalaninemia. In this condition, the child has elevated blood phenylalanine, although it is not quite as high as when there is a complete absence of PAH. In hyperphenylalaninemia, phenylketones do not accumulate.

Transition through the years

Children go through many changes as they grow up, including how they think, what they like and how they take care of themselves. Big changes are often called transitions.

A child must go through a transition in health care when they are diagnosed with PKU. The family and the health-care team can help them learn good health-care habits, the same way they help them learn other life skills. A child who learns good health-care habits will probably have good health habits and attitudes all their life.

This page will help you think about age-appropriate goals for your child. It will give you ideas to help your child become more confident and independent in life and in their health care. It also includes extra goals for children with PKU.

Each child has different abilities from other children. Your child may surprise you with what they can do. Expect good things from your child and encourage them to expect the best from themselves.

Twelve to 14 years old


Teach your teen to speak up for themselves.

Talk to them about body changes in puberty, peer pressure and dating.

Help your teen find positive older role models.

Let your teen know you will answer any question they may have.


Encourage your teen to join teams or clubs at school and to get involved in activities outside of school.

Do not be surprised if your teen enjoys hanging out with friends more than family.

Teach your teen to be assertive and confident about living with PKU and having a special diet. Help them practice these skills.

Cognitive development

Let your teen organize their own school-related work, including assignments and books.

Allow your teen to manage their own school schedule.

Allow your teen to plan and carry out long-term projects for school.

Life skills

Give your teen their own chores and daily responsibilities as well as occasional tasks.

Let your teen plan their own time, including after-school activities, homework and family responsibilities.

Teach your teen money management skills.

PKU care

Have your teen do monthly blood spots on their own.

Have your teen:

  • keep a food record
  • keep a log of protein (PHE) intake
  • prepare and plan their own meals according to protein allowances
  • take part in the special programs offered by the PKU Team

Visit the PKU clinic to see team members and take part in transition education.

Fifteen to 18 years old


Encourage your teen to be a mentor for younger children.

Encourage your teen to work after school or take part in other activities to gain more skills.

Trust your teen, and encourage them to trust you. Talk to them honestly about issues like peer pressure, dating and recreational drugs.


Encourage your teen to be assertive and choose good foods when out with friends or going on dates.

Encourage your teen to keep in touch with friends by phone or email, and allow them to make plans with friends.

Encourage your teen to stay active and to participate both in and outside of school. This will help their self-confidence.

Cognitive (learning) development

Establish a long-term education or career goal. Think about the details. Help your teen make plans for meeting that goal.

Give your teen independence with school work on a day-to-day basis. Let them know you are there for them as support and as a resource.

Encourage your teen to take part in activities that will help them develop new skills.

Life skills

Have your teen shop and run errands for themselves and for family members as needed.

Allow your teen to plan their own time, including after-school activities, homework and family responsibilities.

Talk with your teen about reckless and dangerous behaviours such as smoking, alcohol, drugs and shoplifting. Discuss safe sex with your teen.

Set limits on what you will buy for your teen.

PKU care

Work out a system with your teen for doing blood spots, monitoring their diet and keeping a food record.

Help your teen take charge, but let your teen know that you are there to support them.

Talk about the importance of staying on a PKU diet for life.

Encourage your teen to see the PKU team by themselves and to ask questions and problem-solve with them.

Encourage your teen to read about PKU and to join PKU groups or chat lines such as PKU News on the Internet.

Last updated: November 10th 2009