What is an inherited metabolic disease? Are genetic metabolic disorders common? Inherited metabolic disorders, also known as inborn metabolic abnormalities, are a group of diseases caused by defects in the metabolism of nutrients in the body. Many inherited metabolic diseases can cause brain damage. Genetic metabolic disorders have been identified in more than 500 species, and although the incidence of individual disorders is low, the overall incidence can be as high as 1 in 500 live births. 15-25% of perinatal deaths in developing countries are related to genetic disorders. Genetic metabolic disorders in the neonatal period are one of the causes of neonatal and infant mortality Abnormal neurological manifestations are the most common symptoms of genetic metabolic disorders in newborns. Genetic metabolic disorders in the neonatal period often present with difficulty in sucking and feeding, followed by abnormal breathing, hypothermia or fever, convulsions, and even coma and altered muscle tone. Digestive symptoms such as food refusal, vomiting and diarrhea are also more common. The onset of the disease in the neonatal period is easily misdiagnosed as other common diseases such as neonatal infections and asphyxia, which ultimately delays diagnosis and treatment. Most diseases can lead to death quickly if left untreated. Why is a child with an inherited metabolic disease when the couple is normal and there is no family history of inherited disease? The vast majority of inherited metabolic diseases are autosomal recessive disorders. Each person’s genes are paired, and when one of the parents carries an adverse mutation and the other is normal, the child will not develop the disease; if both parents pass the adverse mutation to the child (1/4 chance), the child will develop the disease; if only one parent or both parents pass the normal gene to the child (3/4 chance), the child will not develop the disease. In other words, the vast majority of inherited metabolic diseases are born to perfectly normal couples! Genetic metabolic diseases need to be diagnosed early and clearly Genetic metabolic diseases usually cause a lot of damage to the body, resulting in stunted growth, low intelligence and neonatal/infant mortality in affected children. With timely identification of the cause of the disease, some of the affected children can have their symptoms reduced or delayed by special feeding. Most importantly, prenatal diagnosis can prevent the recurrence of the condition when the couple has another child.