Tetrahydrobiopterin deficiency is a very rare disorder that increases the levels of several substances, including phenylalanine, in the blood. Most cases of elevated levels of phenylalanine in the blood are caused by a different condition known as phenylketonuria. Tetrahydrobiopterin is a molecule that helps process several amino acids in the body, including phenylalanine.
Signs and symptoms of tetrahydrobiopterin deficiency include
- intellectual disability,
- progressive problems with development,
- movement disorders,
- difficulty swallowing,
- seizures, and
- behavioral problems.
Causes of tetrahydrobiopterin deficiency
Tetrahydrobiopterin deficiency can be caused by mutations in one of several genes, including GCH1, PCBD1, PTS, and QDPR. These mutations are inherited in an autosomal recessive manner, meaning an affected individual must receive one defective gene from each parent, and each parent is an unaffected carrier.
Other tetrahydrobiopterin deficiency symptoms and signs
- Behavioral Problems
- Difficulty Swallowing
- Intellectual Disability
- Movement Disorders
- Progressive Problems with Development
- Seizures
Main Article on Tetrahydrobiopterin Deficiency Symptoms and Signs
Pictures, Images, Illustrations & Quizzes
-
Family Health History: Genetics, DNA Testing and Your Health
WebMD explains why your doctor asks about your relatives' health conditions and how you can get the information if you don’t know.
-
Genetics: 11 Surprising Things Your Genes Say About You
Explore what role DNA plays in your health, love life, and more in this WebMD slideshow.
From 
Parenting & Children's Health Resources
Featured Centers
Health Solutions From Our Sponsors
Subscribe to MedicineNet's Children's Health & Parenting Newsletter
By clicking "Submit," I agree to the MedicineNet Terms and Conditions and Privacy Policy. I also agree to receive emails from MedicineNet and I understand that I may opt out of MedicineNet subscriptions at any time.