Phenylketonuria is a disorder of maternal pku amino acid metabolism, which belongs to recessive genetic disease and has attribute gene abnormalities. Early diagnosis and treatment can prevent nervous system damage caused by high phenylalanine metabolites. If it can be cured within one month after birth, there is usually no mental illness. If found or treated too late, it will cause irreversible damage to the brain.
1、 Etiology of phenylketonuria
1. Gene aspect
In terms of gene technology, the incidence of phenylketonuria in men and women is close to 1:1, and both parents are heterozygotes with normal phenotype. According to Mendel's law of genetic change, 25% of normal development children and homozygous children were born in families, and heterozygotes accounted for 50%. Research on phenylalanine hydroxylase genetic engineering is located on chromosome 12. Different types of gene mutations can be related to race and nationality.
2. Metabolic causes
In fact, phenylalanine is one of the essential amino acids for human body. Under normal conditions, if the body's phenylalanine exceeds the load, this amino acid will undergo a series of changes into tyrosine and be eliminated. The reaction requires phenylalanine hydroxylase. However, if the enzyme activity is reduced or inactive, phenylalanine metabolism is blocked and accumulated in the blood, resulting in unimaginable serious consequences.
2、 Treatment of phenylketonuria
1. Special dietary treatment of phenylketonuria
Phenylketonuria is a special dietary treatment for typical patients with serum phenylalanine levels higher than 1.22 ml / dl (20 mg / dl). L-phenylalanine is a synthetic protein called essential amino acid, which can also damage the nervous system when it is completely lost. Therefore, infants can especially eat low phenylalanine milk powder.
2. Phenylketonuria is treated with drugs
BH4, serotonin and levodopa can be mainly applied to patients with BH4 deficiency. In addition to dietary management control, such patients also need to be controlled by the teaching assistant system through the development of these drugs.
In terms of disease prevention, close relative marriage should be avoided. Early screening and treatment should be carried out in the early stage of pregnancy. For pregnant women with a family history of the disease, a series of prenatal diagnosis should be carried out through DNA analysis in amniotic fluid or pteropterin detection.
In addition, the dietary principle of phenylketonuria is to control the content of phenylalanine in the patient's diet as much as possible, calculate the upper limit of protein intake according to age and weight, and reasonably choose food. The total protein supply must be able to maintain growth and development without aggravating disease. In order to reduce the intake of phenylalanine, the main sources of carbohydrates can be lotus root powder, potato, vermicelli, starch and so on.
In addition, patients should pay attention to supplement enough vitamins and inorganic salts, and choose foods without L-phenylalanine as needed. Patients are restricted in diet for a long time, but their growth and development still need nutritional support. Therefore, the treatment of phenylketonuria should also pay attention to a reasonable diet and actively cooperate with the treatment.