Phenylketonuria: Treatment, symptoms, advice and help
Phenylketonuria (PKU) is a genetic disorder characterized by inability of the body to breakdown a specific type of protein called phenylalanine (Phe). This results in increased level of phenylalanine in the body which may damage the brain tissue, resulting in mental retardation.
Phenylketonuria: Incidence, age & sex
The gene responsible for phenylketonuria is more commonly expressed in people belonging to Ireland, Scotland, Belgium and West Germany. The disease is rarely seen in Blacks, Asians, Native Americans, Jews, and Finns.
Signs and symptoms of phenylketonuria: Diagnosis
Now-a-days, every newborn baby is screened for phenylketonuria, which on detection warrants immediate treatment. Thus classical symptoms and signs of phenylketonuria are rare. A baby with phenylketonuria is normal at birth but may begin to show signs of restricted brain development with sudden decrease in IQ in first year of life. The child may be hyperactive, irritable and show purposeless, repetitive motions. There may be increased muscle tone with an awkward gait. The child may have comparatively lighter complexion than siblings with characteristic blue eyes. There can be a typical musty smell from body discharges (breath, sweat, urine) of the affected baby. Some of them may even develop seizures between the ages of 6 to 12 months.
Generally, the screening test, known as Guthrie test, is performed on the blood sample of a newborn for the detection of phenylketonuria. The increased level of phenylalanine in the blood can be detected in a baby who has started protein diet. In order to confirm the diagnosis, infant’s urine is tested to detect the presence of phenylpyruvic acid. In case of older children, MRI scan is also advised. Majority of children suffering from phenylketonuria may show abnormal EEG (electroencephalogram) patterns.
Causes and prevention of phenylketonuria
Phenylketonuria is genetic disorder, which is transmitted to a newborn from the parents. Since the disorder has an autosomal recessive pattern of inheritance, a baby develops it only when it receives defective genes from both parents.
All newborn babies are recommended to undergo screening test for phenylketonuria. The dietary and other precautions must be followed strictly to avoid complications.
The various complication associated with phenylketonuria develops when the disease is not treated in the early stage. The patient may suffer from arrested mental growth, seizures, and have severe behavioural disturbances. Pregnant women with phenylketonuria may have spontaneous abortions. Some patients may develop agoraphobia (fear of open spaces), low self-esteem and other psychological disturbances if they do not follow the special diet.
A low protein food diet is the main treatment of phenylketonuria. For newborns, special formulas containing low protein with essential vitamins and minerals are advised. The adults and older children can have low protein breads, pastas and cereals with lots of fruits and vegetables in their diet. The babies who receive special diet soon after birth may grow normally and may not develop symptoms of phenylketonuria. However, it is important to continue dietary restrictions throughout life to avoid any complications.