Tetrahydrobiopterin Deficiency

What is tetrahydrobiopterin deficiency?

Tetrahydrobiopterin deficiency is a rare disorder that increases the levels of several substances, including phenylalanine, in the blood. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in all proteins and in some artificial sweeteners. If tetrahydrobiopterin deficiency is not treated, phenylalanine can build up to harmful levels in the body, causing intellectual disability and other serious health problems.

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Tetrahydrobiopterin Deficiency - Symptoms Question: Please describe the symptoms associated with tetrahydrobiopterin deficiency in your child or relative.