There are 21 kinds of amino acids that make up human proteins. Determination of amino acids and their metabolites is important for the diagnosis of congenital or acquired metabolic diseases. Tyrosine can be formed in vivo from phenylpropionic acid, which is oxidized to fumaric acid and acetoacetic acid. Patients with tyrosinemia are caused by defects in tyrosine aminotransferase, often accompanied by myasthenia gravis, hepatosplenomegaly, accompanied by rickets, obvious mental disorders and some congenital malformations. Disease and corneal atrophy, the disease is autosomal recessive. The tyrosine content in the blood of the patient is significantly increased, and a large amount of p-hydroxyphenylpyruvate, p-hydroxyphenyl lactic acid, p-hydroxyphenylacetic acid and tyrosine are excreted in the urine, even when the fasting or tyrosine intake is small. The p-hydroxyphenylpyruvate is often discharged.

Basic Information

Specialist classification: inspection classification: biochemical examination

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:
Reduced in phenylpropionic acidemia.

Normal value:
Serum tyrosine: 33-83μmol/L

Above normal:
Increased in neonates born prematurely (with a transient increase in tyrosine within 1 week of birth) and tyrosine.

negative:

Positive:

Tips: When taking blood, it is necessary to avoid the effects of digestion and absorption of food. It should be taken in the early morning on an empty stomach. Normal value

The fluorescence measurement method was 33 to 83 μmol/L.

Clinical significance

Tyrosine can be formed in vivo from phenylpropionic acid, which is oxidized to fumaric acid and acetoacetic acid.

1, reduced in phenylpropionic acidemia.

2. Increased in neonates born prematurely (with a transient increase in tyrosine within 1 week of birth) and tyrosine.

Neonatal transient hypertyrosinemia, urine excretion of p-hydroxyphenylpyruvate, p-hydroxyphenyl lactate and p-hydroxyphenylacetic acid, which is due to the fact that p-hydroxyphenylpyruvate oxidase is not fully adapted to casein The need for the oxidation process of the acid. Especially in immature children, this enzyme does not have the necessary activity to oxidize a high protein diet to p-hydroxyphenylpyruvate. The activity of p-hydroxyphenylpyruvate was very low during the viviparous period, and it increased rapidly around 36 weeks of gestation.

Patients with tyrosinemia are caused by defects in tyrosine aminotransferase, often accompanied by myasthenia gravis, hepatosplenomegaly, accompanied by rickets, obvious mental disorders and some congenital malformations. Disease and corneal atrophy, the disease is autosomal recessive. The tyrosine content in the blood of the patient is significantly increased, and a large amount of p-hydroxyphenylpyruvate, p-hydroxyphenyl lactic acid, p-hydroxyphenylacetic acid and tyrosine are excreted in the urine, even when the fasting or tyrosine intake is small. The p-hydroxyphenylpyruvate is often discharged.

According to the course of the disease, it can be divided into two types: the rapid deterioration of the baby stage and the cirrhosis and renal rickets. Acute infantile type, sudden symptoms of acute liver failure within 6 months after birth, 90% of those who are not treated will die rapidly, and sometimes have a cabbage-like odor, which is caused by methionine inducer. Some cases can go through the acute type to the chronic type. Chronic type, there will be obvious nodular cirrhosis, rickets caused by renal dysfunction, hypoglycemia, islet cell proliferation and developmental disorders, and more to the end of the liver cancer, most of them died within 5 years old.

Low results may be diseases: Adrenal medulla hyperfunction

1. The plasma amino acid concentration of normal people fluctuates day and night, with a peak at 8 to 10 in the morning and a trough at midnight. When taking blood, it is necessary to avoid the effects of digestion and absorption of food. It is better to take blood on an empty stomach in the morning.

2. If the specimen is not suitable for hemolysis, it may lead to a false increase in the measurement results.

Inspection process

Immediately after venous blood collection, the test method is the same as the amino acid automatic analysis.

Not suitable for the crowd

no.

Adverse reactions and risks

Local congestion occurred.