Genetic Disorders: Phenylketonuria (PKU)

Define Phenylketonuria. This is a rare inherited condition where the infant is born without the capability to properly break down phenylalanine. Also known as PKU. This allows the amino acid (phenylalanine) to build up in the infant’s body. Which means that a diet high in protein can lead to multiple serious health problems because of the dangerous levels that can build up from the incapability of breaking down phenylalanine. For someone diagnosed with PKU, it is a lifelong lifestyle change to follow a diet that limits the intake of phenylalanine which found mostly in proteins.

According to research, PKU is “an autosomal recessive genetic disorder characterized by mental retardation due to a deficiency in phenylalanine hydroxylase, an enzyme necessary to metabolize the essential amino acid phenylalanine to tyrosine. Without phenylalanine hydroxylase, phenylalanine is converted to neurotoxic phenyl pyruvic acid” (Gonzalez, 2009). For those who have PKU, the phenyl pyruvic acid would become quite toxic and lead to damage within the brain causing mental retardation. PKU was first discovered in 1938 by a man named Asbjorn Fölling, and throughout the early 1960s phenyl pyruvic acid was found in urine using a reaction with ferric chloride. However, it was in 1958, that Dr. Guthrie transferred to the Buffalo Children’s Hospital and was able to develop a new approach to measure and monitor

In people with PKU Phenylalanine’s most apparent and benifical side affect is itrs function as a necessary building block for protein; It may also help create chemicals that work to regulate appetite and mood.

These people with are born with a mutated copy of the PKD1 (85% of cases) or PKD2 (15% of cases) gene in each cell and this mutated gene is inherited from one of their affected parents in about 90% of the time. The other 10 percent of cases result from new mutations in people with no history of the disorder in their family. This is known as acquired polycystic kidney disease. The PKD1 gene is located on chromosome 16 and PKD2 gene is located on chromosome 4. Not only are there mutations in the DNA of these genes but there may also be large deletions that remove sometimes up to 10 genes.

PKU, also known as Phenylketonuria, is a genetic disorder that builds up the amino acid phenylalanine in the human body. This genetic disorder is known to be an example of the norm of reaction. The norm of reaction defines itself as a phenotype range that a person with a certain genotype reveals due to the differing of a certain environmental condition. Since this genetic mutation targeted the gene that encrypts the enzyme phenylalanine hydroxylase, it shows that if a person has one and/or two copies of that certain gene, that person would have the ability to eat and metabolize foods with phenylalanine. But, if a person has two copies of the mutated gene, they wouldn’t be able to eat nor metabolize foods with phenylalanine because if a person with PKU were to ingest foods with phenylalanine, the amino acid will accumulate in their body and become highly toxic to the person and the PKU homozygotes will lead to an assortment of detrimental symptoms, which currently occurs in about 1 in 10,000 babies.

Phenylketonuria, or PKU, is an autosomal recessive, heritable disease that decreases levels of the enzyme phenylalanine hydroxylase, which is responsible for the metabolism of the amino acid phenylalanine, resulting in an unhealthy buildup that can lead to brain damage, seizures, and intellectual disability. While not curable, PKU, if detected early on, can be treated to allow sufferers to lead full and healthy lives. The symptoms of PKU appear almost immediately after birth, requiring parents and hospitals to make the necessary preparations, including feeding infants with special formula. Lack of such care can result in

Untreated PKU can lead to brain damage, intellectual disabilities, behavioral symptoms, or seizures. The defective gene does not produce the enzyme necessary to break down and rid the body of phenylalanine. The symptoms of phenylketonuria result from a buildup of (Global Genes, 2012) I eat differently. My friends understand PKU is very difficult, but-non PKU people think I am VERY different. I’ve had to adjust to other’s perceptions and learn to cope with what other people expect is the norm.”(Global Genes, 2012) this researcher would describe this disorder as A birth defect that causes an amino acid called phenylalanine to build up in the body. Phenylketonuria is an internal disorder. delayed development, failure to thrive, short stature, or slow growth

Carol’s line of questioning indicates that she is willing to learn and ready for the nurse to further educate her concerning PKU screening. Carol should be made aware that infants born with PKU are unable to metabolize the amino acid phenylalanine, “...a protein found in milk, dairy products,

Diagnostic exams for PKD are commonly kidney imaging studies, including ultrasounds, CT scans, and magnetic resonance imaging (NKUDIC). According to the NKUDIC, “diagnosis can also be made with a genetic test that detects mutations in the autosomal dominant genes.” Autosomal recessive PDK is diagnosed using ultrasound images of the fetus or newborn, revealing enlarged kidneys or kidneys with an abnormal appearance. It has also been found that higher serum uric acid levels are associated with Polycystic Kidney Disease, according to

ADPKD is a genetically heterogenous disease with mutations in either PKD1 or PKD2 gene. PKD1 gene is located at chromosome 16p13.3 and PKD2 gene localizes to 4q21-22. In Western population about 85% have mutations in PKD1 gene and rest 15% has PKD2 mutations (23-25% in some populations). Patients with mutation in PKD1 gene have more severe phenotype and an early onset disease than those linked to PKD2. Though most of the ADPKD patients have positive family history, about 10% have de-novo mutations. Asymptomatic at-risk family members have 50% chance of inheriting the disease. Previously reported studies have suggested a possibility of a third locus in families that did not relate to mutations in PKD1 or PKD2 gene. However

Large neutral amino acid supplements can be consumed; they block phenylalanine from entering the brain. They can also lower the plasma phenylalanine levels. However, it has been suggested that taking large neutral amino acid supplements has no effect on those who maintain a phenylalanine restricted diet. Sapropterin is another supplement that can be used to lower phenylalanine levels. A study found that those taking 10mg/kg/day of sapropterin had a 30% reduction of plasma phenylalanine levels; of those 30%, 10% of the people had phenylalanine levels higher than 1200 µmol/L. There is also an alternative enzyme therapy under investigation for patients with PKU. This enzyme is an injectable form of phenylalanine ammonium lyase, also known as PegPAL, which is supposed to substitute phenylalanine hydroxylase. This pharmacologic treatment is being investigated for those who do not respond to the treatment of

In the United States, Phenylketonuria (PKU) affects about 1 in 10,000 to 15,000 newborn babies, making it a very uncommon genetic disorder (U.S National Library of Medicine, 2016). Phenylketonuria stems from an abundant buildup of an essential amino acid called phenylalanine that can become very dangerous when it reaches excessive levels (U.S.National Library of Medicine, 2016). The excessive buildup of phenylalanine is caused by an alteration in the gene which codes for the enzyme known as phenylalanine hydroxylase (PAH), which functions in breaking down the aforementioned essential amino acid phenylalanine (U.S National Library of Medicine, 2016). This genetic mutation is caused by an autosomal, recessive genetic mutation in chromosome 12 (Genetic Science Learning Center, 2016).

There are signs and symptoms having to do with this disease. It is present when you are first born, if you are said to have it. However, when they are first born with it, they don’t start encountering problems until they are 6 months or around that age. All states in the United States and their territories, and other places are required to screen for the sickle cell disease on all newborns. Symptoms of this varies from child to child. Some may get symptoms earlier than the next. Early symptoms can be swelling of the hands and feet that is painful. That symptom is known as dactylitis. Another early symptom can be jaundice, which is a yellowish color of the skin. Being fatigue and irritated is another symptom detected early. However, even though there are early symptoms at 5 or 6 months after birth, the doctor can’t predict all the symptoms they will have, when they will start and how severe they will be. Some possible symptoms from the disease would be shortness of breath, being weak and looking pale. Another type of pain you could have is, pain in your bones. The pain can last between a few hours and a few weeks. Some teenagers and adults can have chronic pain that comes from joint damage, ulcers, and other things. The swelling and pain they feel in their feet and hands comes from the sickle shaped red blood cells that are blocking blood from flowing to their hands and feet. Also, abdominal pain is a symptom. Mainly

Problems relating to speech and swallowing may also be present and can worsen over time, eventually interfering with feeding. Those who show symptoms after entering school may survive into adulthood although will experience a progressive decline in intellectual function and may be affected by seizures. The average life expectancy of those affected by the childhood-onset form is 5-15 years of age.

For women with PKU, it's essential that they return to a strict diet if they're considering becoming pregnant, as high phenylalanine levels can harm an unborn child. They have to take particular care during pregnancy as high levels of phenylalanine can damage the unborn baby. Problems can be avoided if phenylalanine levels are strictly controlled during pregnancy and there's no reason why a woman with PKU shouldn't be able to have a normal and healthy baby. All women with PKU has been recommended to plan their pregnancies carefully. They should aim to monitor the blood twice a week and follow a strict diet before becoming pregnant. Pregnancy women will be asked to provide blood samples 3 times a week and will be in frequent contact with their