Discuss the symptoms and effect of Phenylketonuria on the digestive system and homeostasis. What are the available treatments?

naldskee27 | Student

Phenylketonuria-it belongs to the newborn 7 congenital diseases and it is about autosomal recessive metabolic genetic disorder that usually described by a mutation in the gene for the hepatic enzyme phenylalamine hydroxilase (PAH), rendering it nonfunctional. Its symptoms involve the following:

  • Infants with classic PKU usually seems normal until they are a few months old.
  • Seizures , behavioral problems, delayed development  and psychiatric disorders are also common.(being alert or observant is a must when dealing with this type of symptom)
  • for the untreated individuals they usally have a musty or mouse-like odor as a side effect of excess phenylalanine in the body.
  • Children with classic PKU tend to have skinwhich is lighter and hair than unaffected individual, and are also high risk to have skin health condition/disesase such as eczema.

Effect on digestive system and homeostasis

The enzyme normally converts the amino acid phenylalamine into the amino acid tyrosine. If this reaction does not take place, Phe accumulates and tyrosine is deficient or decreased. Excessive phenylalanine can be metabolized into phenylketones through the minor route, a pathway called transaminase with glutamate. For the excessive levels of phenylalanine will usually tend to decrease the levels of other large, neutral amino acid (LNAAs) in the brain. However, as these amino acids are eseential and necessary for protein and neurotransmitter synthesis, Phe buildup hinders the development of the brain, thus causing the infant to have  mental retardation.



If PKU is detected or diagnosed early enough, an affected newborn could still possibly grow up with normal brain function and development, but only by managing and controlling Phenylalamine levels throughproper  diet, or a combination medication and a diet. The diet that we usually  restrict or eliminate are foods high in Phe, such as chicken, meat, fish, chesse, eggs, nuts,  milk, legumes  and other dairy products. In addition, starchy foods, such as bread, potatoes, pasta and corn, must be strictly monitored. The mother will be allowed to give their infants the nutrients from breastfeeding  to provide and get all of the benefits of breastmilk, but the quantity of breastfeeding must stricly monitored also,  and supplementation for the other missing nutrients will be necessary. Lastly, sweetener aspartame, present in many diet foods and soft drinks, must also be avoided, as aspartame contains two amino acids: phenylalanine and aspartic acid that will affect PKU to be more complicated. Experts also try to do several other therapies that are currently under investigation,including what they so called Gene Therapy. Lastly, increase or elevated levels of phenylalanine in the blood and detection of phenylketones in the urine is diagnostic, however majority of patients are diagnosed via newborn screening.