Introduction
Tyrosinemia is a rare metabolic, genetic disorder in the body that cannot break down certain amino acids like tyrosine. It can lead to liver and kidney failure. The condition is seen in newborns. Three types of tyrosinemia are tyrosinemia types 1, 2, and 3. Tyrosinemia type 3 is a congenital condition characterized by an elevated amino acid level. People with this condition cannot break down the building blocks of proteins like tyrosine amino acids. It is caused due to the lack of the enzyme 4-hydroxyphenylpyruvate dioxygenase (4-HDP). The 4-HDP enzyme is required for the breakdown of the amino acid tyrosine. The enzyme is mainly found in the liver and a smaller amount in the kidneys. Tyrosinemia 2 does not involve the liver. The enzyme deficiency is due to the genetic changes in the 4-HDP gene. Tyrosinemia 3 is a rare disorder because few cases of tyrosinemia are diagnosed, and few remain ill-defined. The characteristic features of seizures, mental retardation, loss of balance, and learning problems. Early treatment can prevent the severe outcome of the condition.
What Are the Other Names of Tyrosinemia Type 3?
The other names of tyrosinemia 3 include.
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4-alpha hydroxyphenylpyruvic acid oxidase deficiency.
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4-hydroxyphenylpyruvate dioxygenase deficiency.
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4- alpha hydroxyphenylpyruvate dioxygenase deficiency.
What Are the Causes of Tyrosinemia Type 3?
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Deficiency of Enzyme: Tyrosinemia type 3 is caused by the lack of the enzyme 4-hydroxyphenylpyruvate dioxygenase. It is a hereditary disorder that a newborn cannot make, or there is any defect in the 4-HDP enzyme. As a result, the body cannot break the building blocks of proteins and amino acids like tyrosine. This causes tyrosine, phenylalanine, and methionine to build up toxins in the body. In addition, if the 4-HDP cannot break tyrosine, it may be converted into a harmful acid known as homogentisic acid, which can be dangerous to the body. The human body consists of a small amount of acid and amino acid in the blood, but high levels can be toxic.
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Genetic Inheritance: It is an autosomal genetic disorder in which the child may inherit gene one from each parent. To have a condition, there are two copies of the non-working gene, and one copy may be inherited from each parent. The parents with two copies of the non-working gene do not show signs and symptoms. If the parents are carriers of type 3 tyrosinemia, they can have more than one child with the condition.
What Are the Signs and Symptoms of Tyrosinemia Type 3?
Some people with tyrosinemia type 3 are without signs and symptoms, and others show symptoms. The signs and symptoms are sometimes seen at birth. Signs of the condition have yet to be well known and are variable. Signs and symptoms of the disorder include seizures (epilepsy), mental retardation, difficulty in speaking, loss of coordination, and balance. When the baby starts eating food, the body cannot break down the food. It can lead to a long time for the baby without eating, infections and illness. The enzyme 4-HDP is found in the liver and kidney. The deficiency of the enzyme may lead to liver and kidney failure.
How Can Tyrosinemia Type 3 Be Diagnosed?
Screening newborns at birth is essential to detect tyrosinemia type 3. Therefore, if the newborn screening was out of the normal range, it is necessary to do a follow-up for a confirmatory test to diagnose the cause. The out-of-screening test does not show that the child suffers from a condition. It may occur because of the small blood sample, or the test performed too early. The follow-up test is necessary because untreated tyrosinemia type 3 can show symptoms soon after birth. The blood and urine samples of the newborn baby can diagnose the signs. In addition, the elevation of tyrosine amino acid in the blood may diagnose the condition. The doctor may measure the amount of tyrosine and enzyme 4-HDP to determine the condition's cause. The doctor may prescribe liver function tests for acute and chronic diseases, and the results show abnormal levels, including low albumin levels.
How Can Tyrosinemia Type 3 Be Managed?
The signs and symptoms of the condition are not well known. However, early treatment can help in the healthy growth and development of the newborn. Therefore, to avoid severe disease, treatment is to start early. The treatment of tyrosinemia type 3 is as follows:
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A newborn baby's body cannot break the food. Therefore, the doctor may advise parents to restrict the diet, including proteins and amino acids like tyrosine, phenylalanine, and methionine, because the body cannot break down proteins. These amino acids are found in many proteins and artificial sweeteners. Several foods are available for children in case of tyrosinemia type 3 in the market.
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The doctor may prescribe medications in adulthood and newborns. For example, the doctor may prescribe Nitisinone (NTBC) drugs to treat the condition. The medicine helps to decrease the level of amino acids in the blood because the high level may be toxic to the body.
What Is the Prognosis of Type 3 Tyrosinemia?
The prognosis is good if treated early. The newborn screening is essential for a good prognosis. The child with tyrosinemia type three does not show any physical disability. The other symptoms can be lowered by early and prompt treatment.
Conclusion
Tyrosinemia type 3 is a rare, metabolic genetic disorder in which the newborn body cannot break proteins and amino acids like tyrosine. The main symptom is difficulty in digestion. Early diagnosis and treatment may lower the risks of the disease. Newborn screening and follow-up screening are essential to diagnose the condition. Follow-up screening is important because sometimes the test may show false positive results due to the small amount of blood taken by the laboratory personnel. If the pregnant lady is suffering from tyrosinemia type 3, then the women need to tell the doctor about the condition to start the treatment early and prevent the severe disease risks. Healthcare professionals, including doctors and nurses, can inform parents about the treatment and outcome of the condition.
