Hypermethioninemia in newborns is mostly due to abnormal amino acid metabolism caused by genetic factors. Early symptoms are mainly fatigue and lethargy, which gradually aggravate and show central nervous system symptoms. Symptomatic treatment should be given as soon as possible. Hypermethioninemia in newborns is mostly caused by abnormal amino acid metabolism due to genetic factors. Early symptoms in newborns may appear numbness of the limbs, generalized weakness, lethargy, pallor and other symptoms, the gradual aggravation of the condition will affect the myocardium, reduce myocardial tone, causing bradycardia, heart enlargement, prone to cardiac arrhythmia. Severe hypermethioninemia in newborns will affect the function of respiratory muscles and increase the risk of asphyxia, and at the same time, affect the function of the central nervous system showing irritability, irritability, confusion, and so on. If the newborn is found to have the above symptoms, it is recommended to go to the hospital for consultation and treatment. It is also recommended to pay attention to the feeding and care of the newborn, and to maintain adequate sleep in order to promote recovery.