Custom «Phenylketonuria» Essay Paper Sample

1.0 Introduction

Phenylketonuria (PKU) is defined as the intense deficiency or total absence of the activity of phenylalanine hydroxylase (PAH) that consequently results into alarming elevations of phenylalanine levels in the blood and buildup of phenylketones in the urine of the victim. This kind of inborn error of metabolism is passed from parents to child and it is characterized by the incapability of the body to convert food substances, particularly phenylalanine the essential amino acid (Maria, 2009, p.506). This is because; the patient lacks or suffers deficiency of the phenylalanine hydroxylase, an enzyme that breaks down the constituents of phenylalanine into another form of amino acid known as tyrosine.

2.1 What is meant by an inborn error of metabolism?

Inborn error of metabolism can be described as a group of conditions usually characterized by hereditary imperfection of enzymes and/or other proteins which consequently result into the body's inability to convert food into ready energy. These enzymes are usually helpful in the conversion of food substances into energy and their defect lead into the accumulation of toxic substances which in turn obstruct the normal functioning of the body (Maria, 2009, p. 384).

2. 2 What failure in metabolism occurs in PKU?

Phenylketonuria is an autosomal recessive hereditary error of phenylalanine metabolism that results from shortage or total luck of phenylalanine hydroxylase (PAH) in the body. In most cases, phenylketonuria is caused by alterations on the chromosome 12q23.2 in the phenylalanine hydroxylase gene and it is characterized by insufficiency of PAH (EC1.14.16.1) in the body which is essential for the conversion of Phe to Tyrosine.

2.3 Why does the physician wait for a few days before ordering the PKU test? Why is the test repeated after 2 and 4 week intervals?

A physician must wait for a few days before ordering for a PKU test because the baby has to be on protein for the test to be carried out. Thus these few days is an allowance given to so as to ensure that the baby has received proteins through breast feeding since colostrums is extremely concentrated in these proteins (Maria, 2009). The test is usually repeated after the second and fourth weeks consecutively because the first test is usually considered inaccurate thus a second one is essential.

2.4 Why are the first 2 years of life especially critical for the treatment of PKU?

The first 2 years of the life are especially critical for the treatment of PKU because it is at this period that the infant grows and develops physically, emotionally and mentally. Thus treatment of PKU at this age is very vital since it promotes health mental and physical growth of the infant (Mayor Clinic staffs, 2010).

2.5 If Marcie had not been diagnosed and treated early, with the low phenylalanine formula, what symptoms would she have exhibited?

Generally most infants with PKU seem to be normal at birth but exhibit light coloration and blue eyes after some time. If not diagnosed and treated earlier enough, the infant exhibits symptoms such as irritability, vomiting, bad smell from the urine, and eczema-like rashes on the body (Mayor Clinic staffs, 2010). Some babies show signs of malfunctioning of the nervous system such as amplified muscle tone and hyper active tendon reflexes of the muscles. With time, stern brain problems, such as seizure and mental retardation, develop. Small head, retardation in physical growth and poor maturity of tooth enamel are also some of the symptoms of untreated PKU (Woliver, 2008, p.347). Therefore if Marcie had not treatment timely, she should have exhibited these symptoms.

2.6 Both of Marcie's parents have black hair and brown eyes. How do you explain Marcie's light collaboration?

In most cases, a baby should inherit imperfect genes from both parents in order to develop PKU. An individual with one perfect gene and one imperfect gene grows normally since the perfect gene provides adequate phenylalanine hydroxylase. However, such people are referred to as carries because they do not exhibit the disease themselves but can pass the imperfect gene to their children (Woliver, 2008, p.162). Thus is both parents are carriers, they have 25% chance of giving birth to a child with PKU. Following this argument, it can comfortable be deduced that Marcie's parents are carriers since they do not display any signs of PKU but have passed on their imperfect phenylalanine hydroxylase gene to Marcie who in turn has light coloration.

2.7 Why is it important to include some food containing phenylanein the diet?

While the only treatment for PKU patients is limiting the amount of phenylalanine contents in their daily meals, it is recommended that they include small amounts of phenylalanine in their diet,. This is due to the fact that   phenylalanine is indispensable for normal development and growth therefore if totally omitted from the diet then there is high likelihood that the patient becomes mentally retarded (Maria, 2009, p.84). This diet should, as result, be started at early age, preferably between7-10days, so as to prevent severe mental retardation.    

2.8 What advice would you give Mrs. M regarding relaxing the restrictions?

Diet relaxation is usually conducted after the age of five but it has its own challenges as well. Patients and their families face some difficulties in maintaining the required amounts of Phenylalanine since factors such as illness and fever cause the body to release its own amino acids which in turn raise the levels of phenylalanine in the blood (Mayor Clinic staffs, 2010). My advice to Mrs. M is that she should be careful during the relaxation period particularly when the child is ill so as to ensure that the levels of phenylalanine are well maintained.  

2.9 How long should Marcie have to be on her low phenylalanine diet?

Diet regulation for PKU patients is essential for regulation of phenylalanine levels so that they can be maintained within the enviable range of 2-10mg/dl depending on the intensity of the condition (Mayor Clinic staffs, 2010). Therefore lifelong constraint of phenylalanine in the diet is essential for Marcie in order to endorse maximal growth and cognitive skills.

Phenylketonuria (PKU) can be defined as an inborn error of metabolism that is characterized by insufficient phenylalanine hydroxylase (PAH), an enzyme that is responsible for the conversion of phenylalanine to tyrosine. As a result, levels of phenylalanine become high in the blood and the patient has to constantly regulate the enzyme's level by eating foods that are low in phenylalanine. PKU patients are characterized by light coloration and blue eyes. When not treated on time, PKU can cause severe mental and physical retardation.

4.0 Nutrition Care Plan

The most common and reliable treatment of PKU is a stern diet with very low amounts of phenylalanine and it is recommended that patients stick to this diet for the entire life time. Levels of Phenylalanine vary from one individual to another thus patients require regular monitoring of these enzymes. However, it is advisable that all patients should avoid milk, chocolate, eggs, fish, cheese, peas, nuts, chicken and beans. Rise, pasta, bread cookies and artificial NutraSweet should also be avoided. Special formula for infants, known as Lofenalac is made specifically for infants and can be used in the entire lifetime. The formula is well balanced with the other essential amino acids and is tremendously low in phenylalanine (Mayor Clinic staffs, 2010). This diet should be used immediately after birth through the first two years so as to avoid retardation in mental and physical development.

The best formula for an infant should contain low amounts of proteins and phenylalanine which in most cases are ready available in the formula.