Phenylketonuria
PKU
Quick Facts
Phenylketonuria is "the inherited inability to metabolize phenylalanine that causes brain and nerve damage if untreated." It is a very common disease in the United States and other heavily populated areas such as the United Kingdom. It was discovered in 1934 by a Norwegian scientists named Dr. Asbjorn. Also, it affects newborns but can easily made less severe by keeping a low Phenylalanine diet during pregnancy. (quoted information was taken from dictionary.com)
Foods to Avoid: Meat, Poultry, Eggs, and Fish
These foods are a main source of protein. Since people with PKU or people with a family history of PKU should avoid these things, other proteins such as beans and nuts should be a daily part of their diet.
Foods to Avoid: Milk and Cheese
To get the amount of daily calcium a person needs, people with PKU should opt out milk and cheese for foods like yogurt and leafy green vegetables.
Foods to Avoid: Aspartame (NutraSweet)
Aspartame is found in many foods. Although it would be extremely difficult to avoid completely, try eating foods with low aspartame content , or foods that are not artificially sweetened.
Side Effects
Phenylketonuria has many side effects, though it does not shorten the life expectancy of anyone with this disease. Some are quite harmless while others can be life changing. For example, the mild effects of PKU are behavioral problems, a musty odor to the skin, light hair and skin, low birth weight, and an abnormally small head (this condition is known as microcephaly). Though, PKU can also cause poor mental health, seizures, delayed development, eczema, heart defects, and increased risk of miscarriage. If you or someone you know is experiencing more than one of these symptoms, they may want to consider consulting a doctor.
Eczema
Eczema is one of the symptoms of PKU. It can appear in varying degrees. Such as only slight itching and irritating of the skin as well as a horrible body-covering rash.
Microcephaly
Phenylketonuria can also cause Microcephaly. This is an abnormally small head size. A baby effected by PKU in this way would be born with a normal sized body and a head 1 to 4 sizes too small. As the child grows, their head will still be disproportionate to the rest of their body.
Seizures
PKU can also cause seizures. Although it is very rare, their are cases of patients with PKU.
Diagnostic Tests
PKU can be quite common in highly populated and polluted areas. It occurs in 10,000-15,000 newborns every year. Doctors figure out if a child has this disease by doing diagnostic tests. For example, if a pregnant woman has a family history of PKU they will perform screening tests on the child while it is still in the womb. If they detect the disease, when the baby is born, they will take blood tests after 24 hours of its birth. If you do not have a family history of PKU, your child will still have screening tests done on them. In fact, America is working towards have these tests performed on every baby born in hospitals.
Blood Tests
Blood tests to determine whether or not a baby has PKU are performed with a lancet. It is a small hand held device with a tiny blade inside. They cut a small area of the foot, and collect some of the blood. The baby can hardly feel any of this as it is just a small incision.
Confirmatory Tests
If the initial test for PKU comes out unclear, doctors will perform a confirmatory test. This can either be a urine test (in which they will check the babies acidity levels) or another blood test.
Testing for PKU Before Birth
If your doctor knows that you have a family history of PKU, your baby will be tested for it during an ultrasound.
Inheritance
Phenylketonuria is a single gene mutation. Which means that it is the result of a single gene, in this case it is found on Chromosome 12, that has been mutated. Also, Phenylketonuria is a recessive trait which means that there is a lesser chance of an offspring inheriting PKU.
Inheritance with two "carriers" of PKU
If both parents are carriers of PKU, then there is a 25% chance that their offspring will either be unaffected or have the disease and a 50% chance that their offspring will also be carriers.
Inheritance with one "carrier" parent and one "non-carrier" parent
If one parent is a carrier of PKU and the other is not, their offspring have a 50% chance of being a carrier and a 50% chance of being unaffected.
Inheritance with one parent with PKU
If one parent has PKU, they will pass it on to their children. Even if one parent is completely unaffected, the children will still (at least) be carriers of the disease