From afar, nothing about my cousin’s friend sets him apart from other people. Nothing about him would suggest he has Phenylketonuria (PKU). He does not have any physical signs of being sick or any deformities. Like any normal teenage boy, he is active in sports and is a varsity soccer player. He does well in school and is also friendly, funny, and confident; an all-around nice guy. It is only during lunch outs in fast food joints when he takes out his specially prepared lunch, that one might realize something is different about this certain person.
Phenylketonuria (PKU) is a genetic, metabolic disorder caused by a person’s lack of phenylalanine hydroxylase or PAH (Health Central Network, 2009). This results in the inability to break down and convert amino acid phenylalanine (Phe), a food chemical found in high-protein foods, into other health compounds such as the L-tyrosine compound (MedHelp, 2008). A PKU patient who continues to take food rich in protein will end up with a toxic imbalance of amino acids in the blood and urine, an accumulation of Phe, and low levels of L-tyrosine amino acid (MedicineNet, 2009; eVitamins, 2008).
Collection of unprocessed Phe is harmful to mental functions since brain cells are the most sensitive to the effects of Phe levels (Genetics Home Reference, 2009). Excessive Phe build-up can cause irreversible mental and learning retardation. PKU is also called Phenylalanine Hydroxylase Deficiency Disease and Folling Disease (MedicineNet, 2009). Depending on its type or intensity per person, PKU can also be categorized as Classic or Mild. Classics are the severe cases of PKU patients wherein there is an intense absence of PAH (Genetics Home Reference, 2009).
Untreated Classic PKU patients have the most chances of suffering brain damage due to the dangerously high levels of Phe. On the other hand, Mild PKU cases are for more fortunate patients who have fewer risks for brain defect and require less intense treatment or special diets (MedicineNet, 2009). PKU is also a congenital deficiency and is inherited from parents through an autosomal recessive pattern (Genetics Home Reference, 2009). For a person to become affected by PKU, his or her parents must both be carriers of the mutated gene or the PKU trait (MedHelp, 2008).
PKU carriers do not typically demonstrate signs or symptoms of the deficiency. As such, there is no way for parents to tell that their future child could end up with PKU. Thus, one in every 10,000 Caucasian newborns is found to have PKU. It has a lower percentage of occurrences with children from Asian, Jewish, Finnish, or African backgrounds. PKU occurs the most in newborns from Turkey at a staggering ratio of one in every 2, 600 births (MedicineNet, 2009). Although it occurs with relative rarity, newborn testing for PKU has been mandated in the United States and is routinely practiced in Canada as well.
Screening for PKU enables doctors to accurately diagnose and start treatment of newborns. There are two methods for PKU screening and diagnosis. First is the chorionic villus sampling. It is done during pregnancy. Developing fetuses are checked for PKU by inserting a needle in the woman’s lowed abdomen, or in some cases, a catheter is inserted up the cervix to take a small sample for genetic testing (Mayo Clinic, 2007). The second method is conducted a couple of days after the baby is born. It involves drawing blood sample from the baby which will then be tested for metabolic disorders.
For the test to work properly, the baby should be at least 24 hours old but no more than seven days old, and must have already ingested some protein in the body (Mayo Clinic, 2007). Early diagnosis leads to early treatment which will lead to a more manageable PKU. One should therefore require his or her newborn to go under PKU screening and not rely on watching out for symptoms of the disorder. For infants, PKU symptoms include vomiting, rash or eczema, irritability, musty-smelling urine, and muscle tendon reflexes that are more active than normal (MedHelp, 2008). For the most part however, these characteristics are not obvious signs of PKU.
Most PKU babies appear normal; thus, they grow untreated. At six months, they start to lose interest in their surroundings. At one year, their developments have become totally delayed (National Institute of Child Health and Human Development, 2006). Children with PKU may be overly lethargic, and they may also have poor appetites, extreme sensitivity to light, musty-smelling urine and sweat, fairer hair and skin tones than their family, and diminished mental capacity (eVitamins, 2008). Further symptoms are microcephaly, prominent cheek and jaw bones, end of body growth, and poor teeth development (MedHelp, 2008).
Occurring more frequently than other birth defects, people should be well informed and prepared against the possibility of PKU. The child has a better chance of not developing brain damage despite having PKU if he or she has an early start on PKU treatment. The medical prognosis of PKU can be good when dietary treatment is followed immediately after the child’s birth (All Refer, 2007). Otherwise, brain damage is inevitable. Unfortunately, for some, mental retardation has become the symptom of PKU rather than its effect. For those lucky enough PKU patients who have been correctly diagnosed shortly after birth, a lifetime of treatment follows.
The goal of treatment is to keep the level of Phe in the body within a normal, healthy range through a special diet (Health Central Network, 2009). Phe is an essential amino acid; thus, its total absence within one’s systems is never the goal of treatment. PKU patients must subscribe to a lifetime diet of low protein products such as pasta, bread and cereal, fruits, vegetables, and a special non-Phe formula to provide other important vitamins and minerals that patients cannot acquire from their food (Medline Plus, 2008). Treatment is absolutely important to promote a good quality of life and keep brain retardation at bay.
The average IQ levels of PKU patients are at less than 50 (Health Central Network, 2009). Hence, while not necessarily a fatal disorder, PKU affects one’s capability to function very much. Thus, the survival rate from PKU depends wholly on the one’s discipline and capability to follow the prescribed diet. Following the treatment allows a PKU patient, like my cousin’s friend, to survive and live a good and healthy life. However, many PKU patients find it difficult to adhere to the strict diet, especially during adolescence when the notion of fitting in and being the same as others is important.
Fortunately, studies are being conducted to improve and find new forms of treatment possible. One such research looks into substituting diet therapy with intake of an enzyme called phenylalanine ammonia lyase that will ultimately provide one’s metabolism an alternative Phe (Sarkissian et al. , 2008). Other possible PKU treatments include gene therapy and liver transplant. References All Refer. (2007). Phenylketonuria Prognosis (Expectations). Retrieved January 6, 2009 from http://health. allrefer. com/health/phenylketonuria-prognosis. html. eVitamins. (2008). Phenylketonuria.
Retrieved January 6, 2009 from http://www. evitamins. com/healthnotes. asp? ContentID=1247002. Genetics Home Reference. (2009). Phenylketonuria. Retrieved January 6, 2009 from http://ghr. nlm. nih. gov/condition=phenylketonuria. Health Central Network. (2009). Phenylketonuria. Retrieved January 6, 2009 from http://www. healthscout. com/ency/68/560/main. html. Mayo Clinic. (2007). Phenylketonuria (PKU). Mayo Foundation for Medical Education and Research. Retrieved January 6, 2009 from http://www. mayoclinic. com/health/phenylketonuria/DS00514/DSECTION=tests%2Dand%2Ddiagnosis. MedHelp. (2008).
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