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Clinical and Metabolic Genetics
Clinical and Metabolic Genetics

Phenylketonuria Program

Phenylketonuria Program

The treatment of Phenylketonuria (PKU) is one of the great success stories in metabolic disease. Newborn screening programs, first introduced across Canada through the late 1960's and early 1970's, routinely identify infants with high phenylalanine levels. Diagnosis and treatment can begin within the first few weeks of life and prevent the severe, irreversible mental retardation seen in the past, when treatment was not available.

Best practices now promote that persons with PKU remain on dietary treatment for life. Women with PKU need to be particularly careful during their childbearing years because exposing unborn children to high levels of phenylalanine can cause serious birth defects or developmental delay, a problem known as Maternal PKU.

The PKU program at SickKids provides a comprehensive, family-centered interdisciplinary service including: diagnosis, nutrition management, specialized health assessment and education, support for parents and kids in coping with the challenges of a specialized diet, genetic counseling, and preparation for the child/youth's transition to independent self-management.

In addition, we provide training opportunities for medical residents and fellows, and genetic counselors enrolled in graduate education in the Division of Clinical and Metabolic Genetics and the University of Toronto.

The goal of the PKU Program is to promote optimal physical, developmental and emotional health of young people diagnosed with PKU and Mild Hyperphenylalanemia (MHP).

Team Members

  • Neal Sondheimer M.D., Ph.D., (Medical Director)
  • Dawn Cordeiro R.N., B.N. (Clinic Nurse)
  • Vivian Cruz, M.N. (Nurse Practitioner - Pediatrics)
  • Jolynn Dickson, MSc RD (Dietitian)
  • Sarah Herd, RD (Dietitian)
  • Stacy Hewson MSc, MSc, CGC, CCGC (Genetic Counselor)
  • Maura McClellan (Social Work)
  • Laura Nagy, MSc RD (Dietitian)
  • Nisha Pai, MSc RD (Dietitian)

Home Monitoring of Phenylalanine levels

People with PKU are able to know their blood phenylalanine (PHE) level without having to go to a lab for bloodwork through blood spot home monitoring.

Your PKU nurse will teach you how to do a blood spot test at home for yourself or your child.

Your PKU dietitian and doctor will tell you how often your blood spots should be done.  You can also look on your PKU Clinic Visit Summary Sheet from your last appointment.  At the bottom, we will write how often a blood spot should be done.

Blood spots for people who are seen in the PKU Clinic at The Hospital for Sick Children should be mailed to the address below.  You can also drop off a blood spot in person to the Rapid Response Lab, found on the 3rd Floor, Atrium, Rm. 3642 at The Hospital for Sick Children.  The Rapid Response Lab is open on weekends.

The Hospital for Sick Children
Department of Paediatric Lab Medicine
Rapid Response Lab, Rm. 3642
170 Elizabeth Street
Toronto, ON
M5G 1E8

The Metabolic Laboratory at SickKids currently analyzes blood spots twice a week, on Tuesdays and Thursdays. Please note that if you are dropping off a blood spot to the Rapid Response Lab, it must be received at least one day before the day the blood spots are analyzed. The blood spots cannot be dropped off and analyzed the same day. Also, please note, there can be up to a five day turnaround time to receive results.

Blood spot PHE results are now being mailed to patients once the results are available. If you have sent in a blood spot through the mail, it may take four weeks before you receive the result in the mail. If you want your result sooner, please contact your PKU nurse or dietitian.  If you don’t receive a result in the mail after four weeks, please contact our clinic.

The treatment goal for everyone with PKU is a PHE level that is between 120-360 umol/L.

Women with PKU who are planning to become pregnant may need to have even more strict control of their PHE levels.  If you are a women with PKU planning a pregnancy, please contact your clinic.

If you have questions about how to do a blood spot at home, please contact your PKU nurse.

If you need more supplies for blood spots, please contact Melanie Lameront at 416-813-5753 or melanie.lameront@sickkids.ca.

Initiatives in PKU Clinic

The PKU clinic supports patient education events to share current knowledge and practical tools to help patients and their families manage their disease.  It provides the opportunity for patients and families to meet and learn from one another through education and cooking events.  Our clinic helps facilitate low protein cooking demonstrations conducted by a professional chef and home economist focused on food preparation, meal planning and ideas for low-protein meals/snacks that are tasty and convenient.  The clinic hopes to organize and/or support hands-on cooking events and education sessions for various age groups on an ongoing basis.

We have added one additional clinic each month to the PKU scheduled to improve patient wait times and patient experience.


Adult Patients

Adult patients with PKU have been part of the history of PKU care at The Hospital for Sick Children. However, the care for these patients has now been transitioned to the program at UHN (across the street from SickKids). New patients should contact UHN at

The Fred A. Litwin Family Centre in Genetic Medicine
University Health Network

60 Murray Street, Box 34
3rd floor, Room 400

Toronto, ON M5T 3L9
416-586-4800 x4319

Maternal PKU

Women with PKU or with MHP are referred to the Special Pregnancy Program at Mount Sinai Hospital for specialize management prior to and during a pregnancy.

Sapropterin (Kuvan®)

Sapropterin works by stabilizing any remaining PKU enzyme (PAH) that is present in patients. It works in around one-quarter of patients with PKU. Our program is happy to work with patients to determine whether they are responsive to sapropterin. Patients can be formally tested for responsiveness at age 2.

It is important that patients have coverage for the use of sapropterin, because it is very expensive. For some patients, coverage can be arranged through a health insurance plan. For other patients, we can obtain the medication under a compassionate use agreement with the manufacturer. Current provincial policy effectively prevents coverage under OHIP. Families who are interested in advocating for wider coverage of sapropterin are encouraged to coordinate with CanPKU.

Advances in the World of PKU

PEGylated phenylalanine ammonia lyase (PEG-PAL; aka Pegvaliase) is a new medication that is being studied for use in patients. It is a shot, given under the skin. The medicine works by breaking up phenylalanine as it circulates in the bloodstream. The effectiveness, schedule and dosing for the medication are still being studied. The medication is not yet approved for use, either in the United States or Canada.

Mailing Address

The PKU Program
Division of Clinical and Metabolic Genetics
The Hospital for Sick Children
555 University Avenue
Toronto, Ontario
M5G 1X8

For general inquires contact Melanie Lameront 416-813-5753