甲状腺功能低下症和苯丙酮尿症是两种危害严重的先天性代谢病，患儿如果得不到及时有效的治疗，将会导致智力低下，成为终身残疾。目前在一些城市或地区开展的新生儿筛查工作，就是对初生婴儿进行全面普查，从中检出患儿，在其症状未出现时即给予治疗，保证患儿身心正常发育。? Hypothyroidism and phenylketonuria are two serious congenital metabolic diseases, children without timely and effective treatment, will lead to mental retardation and become disabled for life. Currently in some cities or regions to carry out neonatal screening work is to conduct a comprehensive census of newborn infants, children were detected in the absence of symptoms that give treatment to ensure that children with normal physical and mental development. ?