PKU

Questions

1. What enzyme is most commonly defective in people with phenylketonuria?

PKU occurs when a person inherits a genetic mutation that disrupts the function of a crucial metabolic enzyme (PAH.) 

2. What reaction does this enzyme catalyze? (What is the substrate and what product is produced?)

This is an example of how a block occurs.  This causes a build up of PHe due to the lack of tyrosine.

3. Describe the symptoms of phenylketonuria.

• Delayed mental and social skills
• Head size significantly below normal
• Hyperactivity
• Jerking movements of the arms or legs
• Mental retardation
• Seizures
• Skin rashes
• Tremors
• Unusual positioning of hands

4. What causes the symptoms of PKU, the lack of a substance or the buildup of one?

It is the build up of substances. These substances are harmful to the central nervous system and cause brain damage.

5. How common is phenylketonuria? How is it treated?
 1 in 10000 have it, it is mainly found in Caucasians and east Asains.  It is hardly ever found in African Americans.  Treatment involves a diet that is extremely low in phenylalanine, particularly when the child is growing.