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2nd Dietitians Workshop on PKU

2nd Dietitians Workshop on PKU
  • Endocrinology and metabolism
  • Phenylketonuria (PKU)

Resource type



François Feillet (France) explained that existing protein substitutes are supplemented with vitamins to prevent deficiencies occurring in Phe-restricted diet. Deficiencies, especially of vitamin B series, can worsen PKU neurological symptoms. Dosing vitamins is not always reliable, but it should be performed when there is a suspicion of altered diet or low adherence.

Anita MacDonald (UK) agreed that minerals levels are reassuring in existing protein substitutes. Selenium, zinc and iron status in PKU patients can be deficient in Phe-restricted diet if protein substitute supplements are inadequately taken. Sapropterin in BH4-responsive mild PKU patients significantly improved micronutrient status due to the less-strict diet.

Júlio César Rocha (Portugal) added in the discussion that PKU patients often have low vitamin D3 levels, which can result in reduced bone mineral density over time; DEXA or impedentiometry should be performed periodically together with blood tests because micronutrient status deteriorates with aging due to non adherence to diet and to protein substitute intake.

Anita MacDonald (UK) revealed that the stricter the diet the worse is the quality of life (QoL) in PKU patients while higher blood Phe levels are seen in happier patients. No specific questionnaires are available for PKU patients and parents, evaluating feelings instead of functionality. Both social role and family environment should be evaluated. Sapropterin use may improve QoL by reducing diet-related stress, especially if started early.

Nicole Pallone (Canada) presented the case of her 4yr old daughter who has mild, BH4-responsive PKU, and received sapropterin to counteract the high fluctuating Phe levels despite a strict diet. In two years of therapy, Phe levels normalized and stabilized, allowing for a less restricted diet; no side effects occurred, and cognitive tests were normal.

Sara Boocock (UK) discussed the capability of SMS messages sent by her clinic to young PKU patients to remind them of the monthly Phe testing. The service improved responsiveness up to 20-50%, especially among females and higher-educated patients, with Phe levels notably lower in those positively responding to SMS; but responders reduced with time. She also showed data evaluating selenium and zinc levels in adult PKU patients on diet and supplemented protein substitutes, or not following any diet. Both minerals were often low, selenium more in those on-diet and with good Phe metabolic control, while zinc in those on-diet despite the degree of Phe control and even more in those off-diet.

Natalia Usurelu (Republic of Moldova) discussed the importance of education to families and to society. A diagnosis of PKU means significant changes in the lifestyle not only of patients and their parents but also of their relatives, friends, teachers, caregivers etc. Practical and psychological education about PKU will help with integrating the patient and their family.

Katharina Dokoupil (Germany) illustrated the results of sapropterin use in adult, overweight, BH4-responsive PKU patients with poor metabolic control and not on a Phe-restricted diet. Sapropterin, dosed up to 900mg/day, reduced Phe levels up to 50%, with significant improvement of neurological and behavior symptoms, helping adherence to diet.

Managing sapropterin in mild, BH4-responsive PKU patients during illnesses was discussed by Hulya Gokman-Ozel (Turkey) because of Phe levels increase during infections and inflammation. Further diet restriction should not be performed, decreasing patient defense, while protein substitutes and sapropterin dose should be promptly increased.

Friedrich K. Trefz (Germany) discussed the use of sapropterin in pregnant mild PKU BH4-responsive women, not tolerating a Phe-restricted diet and in bad metabolic control. Sapropterin and low-Phe diet reduced Phe levels and fluctuations avoiding health-related problems to the fetus. No side effects occurred during gestation and after delivery or to the baby.

Kirsten Ahring (Denmark) described the case of a mild PKU BH4-responsive girl who was diagnosed with type 1 Diabetes at 3yrs of age, and received increasing doses of sapropterin (up to 20mg/kg/day). Glucose levels did not lower but in the period of such therapy the overall metabolic control improved probably because of a closer attention to diet.

Laurie Bernstein (USA) reviewed the best tools for educating and motivating PKU patients. Psychological support can counteract children’s embarrassment and frustration, and can also improve family cohesion and diet adherence. Age-tailored educational programs, for example in groups, can build people skills and responsibility.

Eleanor Weetch (UK) and Kristina Motzfeldt (Norway) discussed the management of maternal PKU. Weight control in the mother and Phe levels below 300μmol/l, through an adequate diet that includes folates and essential fatty acids, reduce risks for the developing child, but side effects (i.e. emesis) may complicate its management; breastfeeding is not contraindicated.

Vitamins, minerals and omega-3 deficits may occur in PKU children, said Hulya Gokmen-Ozel (Turkey) and Júlio César Rocha (Portugal), because of the chronically restricted diet, with growth retardation. Low physical activity and excessive caloric intake can lead to overweight quite often. Supplemented and balanced diet can minimize such problems.

Margreet van Rijn (The Netherlands) and Amaya Bélanger-Quintana (Spain) explained how to introduce sapropterin with diet in mild PKU BH4-responsive patients, allowing for lesser protein restriction but still requiring some amino acid supplementation. They also discussed how to adjust its dose according to metabolic control, age targeted Phe levels and in odd situations.

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Rome, Italy
Mar 22, 2012
Target audience
Dietitians, nutritionists, health professional
by Excemed
Endocrinology and metabolism