Phenylketonuria is a very serious autosomal recessive pku handbook amino acid metabolism disease, which was discovered and proposed in 1934. It is named for the high amount of phenylpyruvate in the patient's urine.
The incidence rate in my country is about 1/16500, and it is one of the most common congenital amino acid metabolism diseases in my country. PKU is a treatable hereditary metabolic disease, the condition of which is early diagnosis and early treatment.
Newborns were screened for phenylketonuria in my country. After 72 hours to 20 days after birth, the blood around the heels of the newborns was collected by acupuncture, dripped on special blood collection filter paper, and dried to determine the concentration of phenylpyruvate. If diagnosed, the patient starts treatment 2-3 weeks after birth and the prognosis is good. The older the treatment age, the better the effect.
Phenylalanine is an essential amino acid for the human body, which means that phenylalanine is an amino acid that the human body cannot lack, but it cannot be synthesized by itself and needs to be obtained from external food. Involved in the composition of various proteins in the body. Under normal circumstances, about half of the phenylalanine we take in from the outside world is used to synthesize various proteins, and the rest is converted to tyrosine by phenylalanine hydroxylase. Phenylalanine hydroxylase (phenylalanine hydroxylase) exists in the human liver, and tyrosine is an essential amino acid for the human body. In short, if the essential amino acid is not enough, tyrosine can also play an essential amino acid role . Tyrosine can be metabolized to produce ketone bodies, which can be converted to glucose. Tyrosine can be converted by other enzymes into dopamine, epinephrine, norepinephrine, and melanin.
Among them, phenylalanine hydroxylase is missing and cannot participate in the first reaction, that is, it cannot convert phenylalanine into tyrosine, excess phenylalanine will accumulate in plasma, and the concentration of phenylalanine in plasma is too high. High, excreted by renal metabolism, resulting in phenylpropanolamine urine. To break down phenylalanine, other enzymes convert phenylalanine into phenylpyruvate, which travels throughout the body with the bloodstream, causing tissue damage. Phenylpyruvate accumulates in various tissues such as cerebrospinal fluid, plasma, and urine, and phenylketonuria occurs when urine is excreted. The lack of enzymes occurs precisely because of genetic changes on our chromosomes. The phenylalanine hydroxylase gene is located on chromosome 12. Now research has shown that more than 600 gene mutations have been found that prevent us from synthesizing phenylalanine hydroxylase, thereby affecting our abnormal metabolism of phenylalanine and causing great damage to our nervous system.