POM Block
A GUIDE FOR
PHENYLKETONURIA What is Phenylketonuria?
Phenylketonuria (PKU) is an autosomal recessive disorder that causes the body to be unable to convert phenylalanine to tyrosine due to a deficiency in the enzyme phenylalanine hydroxylase (PAH) or a deficiency in BH4 (tetrahydrobiopterin). Phenylalanine then builds up in the blood, body tissues, and most importantly, the brain. This can lead to intellectual disability, seizures, behavioral issues, and skin related findings1.
Disease Management Phenylalanine should be avoided in patients with PKU, especially in childhood when the brain is rapidly developing . Phenylalanine is a common amino acid found in meat, dairy, seafood, nuts, soy beans, peas, beer, and artificial sweeteners. Patients with PKU may need to cut out many of these foods or eat them in limited quantities to avoid toxic buildup of phenylalanine. Blood levels of phenylalanine are often suggested to be kept at 120-360 μmol/L for children less than 12 and pregnant patients, while patients 12 and older should maintain a blood level of 120 to 600 μmol/L2. BH4
BH2
Tyrosine
Phenylalanine Phenylalanine hydroxylase
Grocery List Suggestions
*must check specific phenyalanine content of each
Recommended:
Limit:
meat and poultry fruits and vegetables lentils and beans butter and oils pastas and breads aspartame (sweetener)
Recipe for Success Breakfast: fruit smoothie with honey and coconut milk with a side of toast Lunch: pasta salad with cucumber, peppers and cherry tomatoes with olive oil and lemon Dinner: stir-fried vegetables with low-protein rice
A Word on Protein Substitutes Protein substitutes are phenylalanine-free amino acid supplements that can be given as capsules, liquids, powders or bars. A protein substitute should be given at each meal to maintain energy/protein requirements as directed by your physician.
1. van Spronsen FJ, Blau N, Harding C, Burlina A, Longo N, Bosch AM. Phenylketonuria. Nat Rev Dis Primers. 2021 May 20;7(1):36. doi: 10.1038/s41572-021-00267-0. PMID: 34017006; PMCID: PMC8591558. 2. MacDonald A, van Wegberg AMJ, Ahring K, Beblo S, Bélanger-Quintana A, Burlina A, Campistol J, Coşkun T, Feillet F, Giżewska M, Huijbregts SC, Leuzzi V, Maillot F, Muntau AC, Rocha JC, Romani C, Trefz F, van Spronsen FJ. PKU dietary handbook to accompany PKU guidelines. Orphanet J Rare Dis. 2020 Jun 30;15(1):171. doi: 10.1186/s13023-020-01391-y. Erratum in: Orphanet J Rare Dis. 2020 Sep 1;15(1):230. doi: 10.1186/s13023-020-01486-6. PMID: 32605583; PMCID: PMC7329487.