Castanet Mireille, Goischke Alexandra, Léger Juliane, Thalassinos Caroline, Rodrigue Daniele, Cabrol Sylvie, Zenaty D, al-Harbi M, Polak Michel, Czernichow Paul
Service d'Endocrinologie, Gynécologie et Diabétologie Pédiatrique, Hôpital Universitaire Necker-Enfants Malades, AP-HP, Paris, France.
Horm Res Paediatr. 2015;83(2):102-10. doi: 10.1159/000362234. Epub 2015 Jan 28.
BACKGROUND/OBJECTIVE: Normally sited glands account for increasing congenital hypothyroidism (CH). Mechanisms often remain unknown. To report the incidence of CH with in situ thyroid gland (ISTG) and describe the natural history of the disease without known etiology.
Clinical, biochemical and imaging data at diagnosis were retrospectively analyzed in 285 children positively screened for CH in Ile-de-France between 2005 and 2008. If treatment was discontinued, management of hormonal substitution and follow-up of biochemical thyroid function was performed.
93 full-term CH neonates displayed ISTG (40.6%), including 50 with unexplained mechanism. Follow-up data were available in 32 of them. Therapy was withdrawn from 20 children at a median age of 23.5 months (6-66), among whom 18 remained still untreated over a median duration of 15.3 months (4.4-29.6). In 11 children, levothyroxine (L-T4) dosage was increased over time to maintain biochemical euthyroidism. No statistical differences in initial TSH or FT4 levels, iodine status or birth weight were found between children with transient and permanent hypothyroidism.
Withdrawal of L-T4 substitution was feasible in 56.2% of full-term children with CH with ISTG but unexplained mechanism, emphasizing the need for systematic therapy withdrawal. However, further studies are warranted to standardize withdrawal protocol.
背景/目的：正常位置的甲状腺导致先天性甲状腺功能减退症（CH）的情况日益增多。其机制通常仍不明确。报告原位甲状腺（ISTG）所致CH的发病率，并描述病因不明的该疾病的自然病程。
对2005年至2008年在法国法兰西岛接受CH阳性筛查的285名儿童诊断时的临床、生化和影像数据进行回顾性分析。如果停止治疗，则进行激素替代管理及甲状腺生化功能随访。
93名足月CH新生儿存在ISTG（40.6%），其中50例机制不明。32例有随访数据。20名儿童在中位年龄23.5个月（6 - 66个月）时停止治疗，其中18例在中位时长15.3个月（4.4 - 29.6个月）内仍未接受治疗。11名儿童随着时间推移增加了左甲状腺素（L-T4）剂量以维持生化甲状腺功能正常。短暂性和永久性甲状腺功能减退症患儿在初始促甲状腺激素（TSH）或游离甲状腺素（FT4）水平、碘状态或出生体重方面未发现统计学差异。
56.2%机制不明的足月ISTG所致CH患儿可停用L-T4替代治疗，这强调了系统性停药的必要性。然而，需要进一步研究以规范停药方案。
