Information for US patients

Life with Phenylketonuria (PKU)


Untreated individuals with PKU appear normal at birth, but if they do not restrict the phenylalanine in their diet, they can develop severe intellectual and developmental disabilities. Other signs and symptoms of PKU may include behavioral problems, slow growth, small head size, eczema or skin rashes, seizures, jerking movements of the arms or legs and musty odor of breath, skin or urine. Signs also include fair skin and blue eyes, due to the body’s failure to transform phenylalanine into melanin, the pigment responsible for a person’s coloring.¹

Lady in a florist


Family together at beach



The first line of therapy to treat PKU is a phenylalanine-restricted diet. This involves medical foods which have been modified to be low in protein and medical formula (a special nutritional supplement as directed by your healthcare provider) which provides the nutrients a person without PKU would typically get from protein.²

Make sure you always talk to your dietitian before considering any new foods or changes to your diet plan.

In addition to the phenylalanine-restricted diet, some patients with PKU also take a medication called sapropterin dihydrochloride, the active ingredient in JAVYGTOR. This medication helps the PAH enzyme work more effectively to break down phenylalanine in the body.²

JAVYGTOR is not a cure for PKU, but when combined with a phenylalanine-restricted diet it can help keep phenylalanine levels under control,³ and may help you better manage your condition.

Find out more about the PKU dietFind out more about JAVYGTOR


1. National Institutes of Health. What are common symptoms of phenylketonuria (PKU)? Available at: (Accessed: February 12th, 2024).

2.Vockley J., et al; for the American College of Medical Genetics and Genomics Therapeutic Committee. Phenylalanine hydroxylase deficiency: diagnosis and management guideline. Genet Med. 2014;16(2):188-200. doi:10.1038/gim.2013.157.

3. JAVYGTOR (sapropterin dihydrochloride). Prescribing Information. Dr Reddy’s Laboratories Ltd.