Phenylketonuria (PKU) is a rare genetic disorder that affects the body's ability to process an amino acid called phenylalanine. This condition is caused by a mutation in the gene responsible for producing an enzyme called phenylalanine hydroxylase (PAH). Without this enzyme, phenylalanine builds up to toxic levels in the blood and can cause severe health problems.
PKU is inherited in an autosomal recessive manner, which means that both parents must carry a mutated copy of the PAH gene for their child to be affected. If both parents are carriers, there is a 25% chance with each pregnancy that their child will have PKU, a 50% chance that the child will be a carrier like the parents, and a 25% chance that the child will neither have PKU nor be a carrier.
Carriers of PKU do not typically show any symptoms of the disorder because they have one normal copy of the PAH gene that produces enough functional enzyme to metabolize phenylalanine effectively. However, they can pass the mutated gene on to their children.
It is important to note that not all individuals with PKU inherit the disorder from their parents. In about 1-2% of cases, PKU occurs due to a spontaneous mutation in the PAH gene, meaning it is not inherited from either parent.
Genetic testing can be performed to determine if an individual is a carrier of PKU or if they have the disorder. This involves analyzing the DNA to identify any mutations in the PAH gene. If both parents are known carriers, prenatal testing can also be done to determine if the fetus has inherited PKU.
Once diagnosed with PKU, individuals need to follow a strict low-phenylalanine diet to prevent the buildup of phenylalanine in their bodies. This involves avoiding foods that are high in protein, as phenylalanine is found in most protein-rich foods. Additionally, individuals with PKU may need to take a special formula that provides the necessary nutrients while limiting phenylalanine intake.
Early detection and treatment of PKU are crucial to prevent the development of intellectual disabilities and other health complications associated with the disorder. Regular monitoring of blood phenylalanine levels and close medical supervision are essential for managing PKU throughout a person's life.
In summary, Phenylketonuria (PKU) is a hereditary disorder caused by a mutation in the PAH gene. It is inherited in an autosomal recessive manner, meaning both parents must carry a mutated copy of the gene for their child to be affected. Genetic testing can determine if an individual is a carrier or has PKU. Following a low-phenylalanine diet is necessary to manage the condition and prevent complications. Early detection and treatment are crucial for optimal outcomes.