Diagnostic points: 1. Clinical features (1) Symptoms Newborns may have less food, less crying, less movement, delayed discharge of fetal stool, and delayed resolution of jaundice. Typical symptoms often become apparent 3 to 6 months after birth. (1) growth retardation and dwarfism; (2) low intelligence; (3) various physiological functions; (2) physical signs ① special facial features facial mucous edema, puffy eyelids, wide eye spacing, collapsed nose, thick lips and large tongue; (2) special body posture short stature, large head, long trunk, short limbs, and bulging abdomen. (3) Hair and skin changes Hair is yellow and thin, skin is rough. (2) Laboratory and other tests (1) Skeletal X-ray examination Bone age lags behind the actual age, newborns and small infants have knee radiographs, and left hand bone radiographs are taken over 1 year of age. (2) Thyroid function tests Serum T3, T4, TSH measurement first shows a rise in TSH, then a fall in T4, and finally a fall in T3. (3) 99m-TC thyroid gamma imaging can show absence, ectopic or dysplasia of the thyroid gland. (4) Newborn screening The hormonal changes in children with CH usually precede the clinical manifestations, so early diagnosis is mainly based on laboratory tests. In newborns at 3 days of age, peripheral blood is taken from the medial and lateral edges of the heel, dripped onto a filter paper sheet, dried and sent to a screening center for testing. 3. Diseases that need to be differentiated: chondrodysplasia, mucopolysaccharidosis, trisomy 21, growth hormone deficiency, etc. Treatment points: After the diagnosis is established, thyroid preparations should be taken as soon as possible to maintain normal physiological functions. 1. The drug can be levothyroxine (L- T4 4-10μg/kg daily, 1 time/day, morning dose) or thyroid tablets (2-5mg/kg daily, divided into 2-3 oral doses). Adjust the drug dosage according to blood T3, T4 and TSH until clinical symptoms improve and serum T3, T4 and TSH return to normal, and use this as the maintenance amount. Pay attention to the individual differences of drug dosage, only TSH rise is appropriate to reduce the dose. 2.Strengthen education and training to make progress in intelligence; diet should be rich in calories, protein, vitamins and minerals (such as calcium, iron, etc.). 3.Vitamins A, B, C and D should be supplemented according to clinical needs. 4.Calcium should be supplemented after the growth rate is accelerated, and iron should be added for anemia.