Special rat odor in urine

The patient's liver cannot synthesize tyrosine alanine hydroxylase, so that phenylalanine in food cannot be oxidized to tyrosine, but can only be transaminated into phenylpyruvate in the kidney. Phenylalanine and other metabolites have a toxic effect on the development of nerve cells, while the barrier to the formation of tyrosine affects the formation of myelin sheaths during the development of nerve fibers. Its clinical features are severe mental retardation, with speech impairment being the most severe, and 85% of patients are at the level of dementia. Accompanied by motor dysfunction, muscle tension is high or low, can not sit down, can not walk, or sway the body while walking. The hair is light or yellow, the skin is fair, and the eye iris pigments are yellow or light blue, which is typical of skin color. Eczema on the skin is also common, and urine has a special rat urine odor. May have cone tract signs and other pathological reflexes. EEG is abnormal in most patients. Excess phenylpyruvate is excreted in the urine. In most cases, simply controlling the intake of phenylalanine in the diet after birth can successfully prevent brain damage. Neonatal patients can be asymptomatic, but irreversible brain damage can occur if treatment is delayed for one year, so early diagnosis and treatment are extremely important. Incidence rates vary widely around the world, and are rare among black races, with an incidence of 1: 16000 in China.