Newborn disease screening is necessary to do, most congenital genetic metabolic diseases, normal performance at birth, growth and development process gradually appear symptoms, such as hypothyroidism, early symptoms are light, a few months or 1-2 years old, can be found with the normal child growth is different; phenylketonuria, no difference with normal children at birth, a few months later the hair from black to yellow, fairer skin tone, urine, sweat has a special smell, on The impact on intelligence is greater. Blood is collected 3 days after birth, early detection, intervention and treatment, intelligence can be normal, after the development of intelligence and then intervention, the impact on intelligence, it is difficult to reverse.