{"id":38,"date":"2023-02-22T12:01:43","date_gmt":"2023-02-22T12:01:43","guid":{"rendered":"https:\/\/pku.biomarin.com\/en-us\/?page_id=38"},"modified":"2025-09-29T10:34:05","modified_gmt":"2025-09-29T10:34:05","slug":"phe-in-the-brain","status":"publish","type":"page","link":"https:\/\/pku.biomarin.com\/en-us\/about-pku\/phe-in-the-brain\/","title":{"rendered":"PHE in the brain"},"content":{"rendered":"
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With PKU, it’s all about protecting your brain\n<\/h1>\n\t\t\t\t\t\t\t\t\t\t\t\t\n

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What is PKU?<\/h2>\n

PKU is short for phenylketonuria, also known as PAH deficiency, which is a rare genetic condition. In the U.S., about 17,500 people are living with PKU and approximately 350 babies are born with it each year. People affected by PKU have difficulty breaking down phenylalanine (Phe), an amino acid found in all natural protein.<\/p>\n <\/div>\n \n

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Food impacts blood Phe levels.<\/h2>\n

The reason people with PKU can’t break down Phe is that they have a problem with an enzyme called phenylalanine hydroxylase (PAH). PAH breaks down Phe into another amino acid called tyrosine.<\/p>\n

Since Phe is found in many foods, such as chicken, meat, eggs, dairy, nuts, grains, and legumes, people with PKU typically eat a special diet.<\/p>\n

Learn how you can prevent high blood Phe levels<\/a><\/p>\n <\/div>\n \t\t<\/div>\n\t<\/div>\n<\/div>\n\n

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PKU affects the brain.<\/h2>\n

The signaling molecules that brain cells use to communicate with each other are called neurotransmitters. When neurotransmitters are not made in the right amounts, the brain cannot function properly. High blood Phe levels can cause disruptions in neurotransmitters like serotonin and dopamine, which are important for mood, learning, memory, and motivation.<\/p>\n

In addition to disrupting neurotransmitter balance, Phe itself can be directly toxic to the brain. Scientists think that these changes are behind how high blood Phe affects the way a person thinks, feels, and acts.<\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n

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Symptoms of high blood Phe levels.<\/h3>\n

When Phe levels are high or uncontrolled, people with PKU can experience symptoms that have lasting impacts on the brain. Symptoms of high or unstable blood Phe levels include:<\/p>\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n

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