Congenital Hypothyroid sm 先天性甲状腺功能减低症 Xue Fan gu. Md. Phd Xinhua Hospital Shanghai jiao Tong University School of medicine
Congenital Hypothyroidism 先天性甲状腺功能减低症 Xue Fan Gu, MD, PhD Xinhua Hospital Shanghai Jiao Tong University School of Medicine
Incidence Thyroid hormone deficiency may: or acqulre d Congenital: most cases are hypoplasia or aplasia of the thyroid gland World:1:3000~5000 China: 1: 3 200
Incidence • Thyroid hormone deficiency may: or acquired • Congenital:most cases are hypoplasia or aplasia of the thyroid gland World: 1:3 000～5 000 China: 1:3 200
Thyroid Ontogenesis 0 8th gestational weeks: synthesis of thyroglobulin 0 10 12th gestational weeks: pitutary gland begins to secrete TSh, thyroid gland synthesis of T3, T4 30th gestational weeks: hypothalamic pitutary-thyroid axis is functioning and independent of the maternal axis
⚫ 8th gestational weeks: synthesis of thyroglobulin ⚫ 10~12th gestational weeks: pitutary gland begins to secrete TSH,thyroid gland synthesis of T3、T4 ⚫ 30th gestational weeks: hypothalamicpitutary-thyroid axis is functioning and independent of the maternal axis Thyroid Ontogenesis
After delivery .14 TSH rapidly 300 10 rise reaching 250 60~80uU/ml 10 levels, and then200、 8 slowly decline 150 over the next 6 few days(5-7d) 100 to <suU/ml 50 T3 2 levels 30 Birth 2 4 6 GESTATIONAL POSTNATAL AGE (wks) AGE(wks)
• After delivery, TSH rapidly rise reaching 60~80 uU/ml levels, and then slowly decline over the next few days(5~7d) to <5 uU/ml levels
Thyroid hormone synthesis and metabolism The thyroid follicle is stimulated by tsh by increase with TSH receptor Iodine from the circulation is concentrated and rapidly oxidized by peroxidase to iodine Iodine incorporated into tyrosyl residures on thyroglobulin Iodothyrosines are couple an ether linkage to form T4 and T3
Thyroid hormone synthesis and metabolism • The thyroid follicle is stimulated by TSH by increase with TSH receptor • Iodine from the circulation is concentrated and rapidly oxidized by peroxidase to iodine • Iodine incorporated into tyrosyl residures on thyroglobuline • Iodothyrosines are couple an ether linkage to form T4 and T3
IT DIT甲状腺胶质 T MIT DIT Tyr MIT T3 Ta T yI DIT Tyr 胶质小滴 溶酶体 s吞噬溶酶体 條 球蛋 MIT TG DIT T 碘泵 TO T T4
·T3andT4 Meta bolic potency of t3 is 3-4 times that of T4. Only 20% of circulating t3 is secreted by the thyroid 3. T4 in circulation Binding form: 70% with TBG, other with alb Free form: T40.03%. T30.3%0
• T3 and T4 • Metabolic potency of T3 is 3~4 times that of T4. Only 20% of circulating T3 is secreted by the thyroid • T3, T4 in circulation Binding form：70％with TBG ，other with Alb. Free form：T4 0.03%, T3 0.3%
Hypothalamus TRH Anterior pituitary gland TSHT Thyroid gland r3 3 4 Hypothylamic-pitutary-thyroid feed back regulation
TRH TSH - Hypothalamus Anterior pituitary gland Thyroid gland rT3 T3 T4 Hypothylamic-pitutary-thyroid feedback regulation
Physiological of thyroid hormones Increase oxygen consumption Stimulate protein synthesis Influence growth and differentiation Affect carbohydrate, lipid and vitamine metabolism
Physiological of thyroid hormones • Increase oxygen consumption • Stimulate protein synthesis • Influence growth and differentiation • Affect carbohydrate, lipid and vitamine metabolism
Etiology The cause may be sporadic or familial, goitrous or nongoitrous Defective embryogenesis 75 genesIs, dysgenesIs, ectopia Dyshormonogenesis Pit-1, TSH, TSHR, TTF-L TTF-IL, Pax 8, TG, tPO defect, etc. lodide transport defect, organification defect coupling defect, iodotyrosine deiodinase defect, ina bility of tissuses to convert t4 to T3 Deficiency or excess of iodine
Etiology • The cause may be sporadic or familial, goitrous or nongoitrous • Defective embryogenesis 75% Agenesis, dysgenesis, ectopia • Dyshormonogenesis Pit-1, TSH, TSHR, TTF-I, TTF-II, Pax 8, TG, TPO defect, etc. Iodide transport defect, organification defect, coupling defect, iodothyrosine deiodinase defect, inability of tissueses to convert T4 to T3 • Deficiency or excess of iodine