PKU is the rare condition that the baby is born without the ability to break down an amino acid called phenylalanine. This birth defect is rare because it takes 2 parents that are carriers of the disease to have a child and even than its still rare for any of the kids to become anymore than carriers. Babies that are born with PKU are missing an enzyme called phenylalanine hydroxylase which are needed to break down the essential amino acid called phenylalanine. The amino acid phenylalanine is found in foods that contain protein such as meats and fish and other types of food that contain protein. Without this amino acid your body starts to build up high levels of phenylalanine which are harmful to the central nervous system and can cause brain damage.
This disease affects your melin which is what decides your hair and skin colors this disease has symptoms that are more obvious than others some symptoms are * Delayed mental and social skills
* Head size significantly below normal
* Jerking movements of the arms or legs
* Mental retardation
* Skin rashes
* Unusual positioning of hands
PKU is actually a treatable birth defect un like most really all you have to do is follow a strict diet. Also when a baby use a special formula and it can be used for the rest of your life for protein source without phenylalanine if you follow this diet than its easy to have a long and healthy life. People with PKU normally look perfectly fine only difference could be lighter skin and lighter hair than brothers