Genetic Disease Research Paper: Phenylketonuria (PKU)

Phenylketonuria (PKU)
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Phenylketonuria (PKU)
Phenylketonuria is an inherited disease that heightens the amount of substances referred to as phenylalanine (Phe) in the bloodstream (Genetic and Rare Diseases Information Center, 2018). Phenylalanine is a building block, which is found in an individual’s diet. All proteins contain phenylalanine, as well as some artificial sweeteners. When the levels of the enzyme phenylalanine hydroxylase (PAH) reduce in the body, they disable the body’s ability to metabolize the important amino acid phenylalanine. Eventually, the phenylalanine levels increase to harmful levels in the blood (Genetic and Rare Diseases Information Center, 2018). The signs of PKU can either be severe or mild; however, when left untreated PKU can lead to serious health issues such as intellectual disability. The classic PKU is regarded as the most severe. Individuals with classic PKU show signs of neuropsychiatric complications and intellectual deficit. The conditions rarely occur with an estimation of about one to fifteen thousand births (Thiele et al., 2017). Classic PKU is associated with near complete or complete deficiency of phenylalanine hydroxylase. Individuals with classic PKU also have behavioral issues, developmental delays, seizures, and light skin and hair. For mothers with PKU, failing to adhere to the phenylalanine-restricted diet can increase the mother’s chance of giving birth to children with a similar condition of PKU. A majority of reports involving PKU highlight that the disorder is caused by changes in the PAH gene. PKU forms an important topic for discussion since the disease is among the various inherited metabolic diseases that represent a high risk for disturbing an individual’s growth.
Gene
The gene responsible for the disease is phenylalanine hydroxylase (PAH), which is found in chromosome 12 (Thiele et al., 2017). The phenylalanine hydroxylase is useful in converting amino acids phenylalanine to another amino acid referred to as tyrosine. The mutation that occurs in both copies of the PAH gene indicates that the enzyme is either less efficient or inactive. As a result, the amount of phenylalanine building up in the body can rise to toxic levels. Individuals can also experience mild forms of PKU, which is referred to as hyperphenylalanemia, in some mutations of PAH. Nonetheless, the diseases are both caused by mutations that take place in the PAH locus. Mild mutation can occur in scenarios whereby the individual is heterozygous for the two mutations of PAH.
Transmission
The transmission of Phenylketonuria is autosomal recessive, meaning that it is passed down to an individual through a family member (Mayo Clinic, 2019). This requires two copies of abnormal genes to be present so that the disease can develop. Transmission occurs from the mother to their infant. Infants whose mothers have PKU will have at least one abnormal gene for PKU, which they will inherit from their mother’s homozygous-infection. Nonetheless, the possibility of infection is approximately one in every sixty children meaning that the inheritance less likely to occur. For affected mothers, roughly one in twelve children are likely to ...