Phenylketonuria (PKU) is a rare genetic disorder that affects the body's ability to break down phenylalanine. Without treatment, it can lead to severe disabilities. Symptoms include intellectual disability, developmental delays, seizures, and a musty odor. Early diagnosis through newborn screening is vital. Treatment involves a low-phenylalanine diet and, in some cases, medication. Proper management can help individuals with PKU lead healthy lives. Ongoing research aims to improve treatment

Best medications for PKU

Drug NameClassRouteStandard DosagePrice
JavygtorEnzyme Replacement TherapiesOral500, 100 MGfrom$341.47
KuvanEnzyme Replacement TherapiesOral500, 100 MGfrom$341.47
PalynziqEnzyme Replacement TherapiesSubcutaneous2.5, 20, 10 MG/0.5MLfrom$636.79

Phenylketonuria (PKU)

Phenylketonuria (PKU) is a rare genetic disorder characterized by the inability to properly break down an amino acid called phenylalanine. This condition affects the way the body processes protein, leading to a buildup of phenylalanine in the blood. If left untreated, this accumulation can cause severe mental and physical disabilities.

Causes and Symptoms

PKU is caused by a deficiency of an enzyme called phenylalanine hydroxylase, which is responsible for converting phenylalanine into another amino acid called tyrosine. Without this enzyme, phenylalanine levels rise and can negatively affect brain development and function. The symptoms of PKU can vary in severity and may include mild to profound intellectual disability, delayed development, behavioral problems, seizures, skin rashes, and a musty odor in the breath, skin, or urine. Newborns with PKU often appear normal at birth, but without early detection and treatment, they may begin to show signs of developmental delay within a few months.

Diagnosis and Treatment

PKU is typically diagnosed through newborn screening programs, which involve a blood test to measure phenylalanine levels shortly after birth. Early detection is crucial to prevent the development of symptoms and minimize the long-term effects of the disorder. The primary treatment for PKU involves following a strict low-phenylalanine diet. This diet restricts the intake of high-protein foods such as meat, fish, eggs, dairy products, and certain grains. Instead, individuals with PKU must consume specially formulated medical foods and formulas that provide the necessary nutrients without excess phenylalanine. The diet must be strictly adhered to throughout life to prevent complications. Additionally, some individuals with PKU may require the use of medication called sapropterin (Kuvan). Sapropterin is a synthetic form of tetrahydrobiopterin, a cofactor that helps the body process phenylalanine more efficiently. It can be used to lower phenylalanine levels in certain individuals with BH4-responsive PKU, a milder form of the condition.


With early diagnosis and proper management, individuals with PKU can lead healthy lives. Following a low-phenylalanine diet and monitoring phenylalanine levels are essential to prevent cognitive impairment and other complications associated with the disorder. Regular medical follow-ups and ongoing support from a healthcare team experienced in managing PKU are crucial for long-term care. Research is ongoing to develop new treatments and therapies for PKU, including gene therapy and enzyme replacement therapy. These advancements hold promise for improved outcomes and may provide additional options for individuals with PKU in the future. In conclusion, PKU is a genetic disorder that requires lifelong management. Early detection, strict adherence to a low-phenylalanine diet, and appropriate medical care are key to preventing complications and promoting the best possible outcomes for individuals living with PKU.