Phenylketonuria Definition
Phenylketonuria, or PKU, is a rare genetic disorder that causes an amino acid called phenylalanine to build up in the body. Amino acids are the building blocks of proteins, and phenylalanine is found in all proteins and some artificial sweeteners.
This condition is caused by a defect in the gene that helps create the enzyme needed to break down phenylalanine. Without this enzyme, the body cannot process phenylalanine, resulting in phenylalanine building up in the blood and brain. If left untreated, phenylketonuria can cause permanent brain damage and several other health problems in sufferers.
Meanwhile, based on the severity, PKU is divided into two types, namely:
- Classic PKU. The most severe form of the disorder is called classic PKU. This type of PKU is characterized by the enzyme needed to convert phenylalanine being missing or severely reduced. As a result, phenylalanine levels rise dramatically, leading to severe brain damage.
- A less severe form of PKU. In mild or moderate forms, the enzyme retains some function, so phenylalanine levels are not as high as in classic PKU. In this type of PKU, the risk of brain damage that lurks in sufferers will also be lower when compared to classic PKU.
Symptoms of Phenylketonuria
Phenylketonuria usually does not cause symptoms in newborns. If the condition is not recognized and treated at birth, symptoms may not appear until months later. Signs of untreated phenylketonuria typically include:
- Intellectual disability or mental retardation.
- Behavioral, emotional, and social disorders. For example, frequent tantrums.
- Slow growth.
- Epilepsy.
- Tremors.
- Frequent vomiting.
- Skin disorders, such as rashes.
- Musty odor in the child’s breath, urine, skin, or hair.
If treated early, phenylketonuria rarely shows symptoms later in life. Early health checks in infants are very important. Not only to detect the potential for phenylketonuria, but also various other serious health conditions.
Pregnant women with phenylketonuria should also have regular check-ups and maintain their diet during pregnancy. This is because high levels of phenylketonuria in the blood of pregnant women can be dangerous for the fetus, because it has the potential to cause miscarriage.
Causes of Phenylketonuria
Genetic mutations, whether mild, moderate or severe, are the main cause of phenylketonuria. These mutations then cause the phenylalanine hydroxylase gene to not produce the enzyme that breaks down phenylalanine in the sufferer’s body. Unfortunately, until now the cause behind these genetic mutations is not yet known for sure.
Experts believe that the condition is also closely related to heredity. If both a mother and father have the trait of phenylketonuria, the child will have about a 25 percent chance of developing the condition.
Phenylketonuria Risk Factors
The following factors can increase a baby’s risk of developing phenylketonuria:
- Having both parents with the gene defect that causes phenylketonuria.
- Being of a certain ethnicity. The gene defect that causes phenylketonuria varies by ethnic group. Phenylketonuria is more common in other ethnic groups outside of African-Americans.
Diagnosis of Phenylketonuria
If you have PKU or a family history of it, your doctor will recommend a screening test before pregnancy or birth. The screening test will be done through a blood test to identify the gene that carries PKU. While
In addition, phenylketonuria can also be detected by screening newborns by taking blood samples. The screening test is performed when the baby is one to two days old, usually still in the hospital. In addition, additional tests may need to be performed to confirm the initial test results. The additional tests aim to look for the presence of PAH gene mutations that cause phenylketonuria.
If symptoms of phenylketonuria are experienced by children or adults, such as growth retardation, the doctor will recommend a blood test to confirm the diagnosis. This test involves taking a blood sample and analyzing it for the presence of an enzyme needed to break down phenylalanine.
Complications of Phenylketonuria
Phenylketonuria left untreated can cause several complications in sufferers, both in infants, children, and adults. Here are some complications that can occur due to phenylketonuria:
- Permanent damage to the brain that can lead to learning disabilities.
- Nervous disorders, such as tremors or seizures.
- The head size is small, so it looks unnatural.
- Birth defects or miscarriage.
Phenylketonuria Treatment
Unfortunately, phenylketonuria cannot be cured. Treatment can only control the levels of phenylketonuria in the body so as not to trigger symptoms and complications. Here are some treatments that sufferers need to do to overcome phenylketonuria:
- Taking amino acid supplements. This step is useful to fulfill the nutrition needed by the body for growth.
- Maintaining the level of phenylalanine in the body is not excessive. Before changing the diet, every sufferer is advised to always discuss it with a doctor.
- Regular health checks are also needed to prevent possible complications.
Prevention of Phenylketonuria
PKU is a genetic condition, so it cannot be prevented. However, if you have PKU and are considering getting pregnant, there are a few things you need to do, namely:
- Perform an enzyme test. This is a blood test that can determine whether or not a person carries the defective gene that causes PKU. It can also be performed during pregnancy to screen an unborn baby for PKU.
- Follow a low-phenylalanine diet. Women with PKU can prevent birth defects by following a low-protein diet. It is recommended to avoid protein-rich foods such as eggs, dairy products, fish, and all types of meat. Other types of food should also be carefully selected and measured, including vegetables and fruits.
Therefore, if you have PKU, consult your doctor first before you start trying to get pregnant.
When to See a Doctor?
Seek medical help immediately if you experience any of the following conditions:
- In newborns. If routine newborn screening tests show signs that your baby may have phenylketonuria, your pediatrician will start dietary treatment right away to prevent long-term problems.
- In women of childbearing age. It is very important for women with a history of phenylketonuria to see a doctor and maintain a phenylketonuria diet before and during pregnancy. The purpose is to reduce the risk of increasing phenylketonuria levels that can harm the fetus.
- Adults with phenylketonuria must receive lifelong treatment and have their condition checked regularly by a doctor.
