PLACENTAL TRANSFER OF MATERNAL ANTI-RABBIT IgG CAUSING FALSELY ELEVATED TSH LEVELS IN NEONATES

Abstract. Larsson, A., Hedenborg, G. and Carlström, A. (Department of Paediatrics, Karolinska Institute, St. Göran's Children's Hospital, and the PKU Section, Department of Bacteriology, National Bacteriological Laboratory, Stockholm, and the Department of Clinical Chemistry, Karolinska Institute, Danderyd's Hospital, Danderyd, Sweden). Placental transfer of maternal anti-rabbit IgG causing falsely elevated TSH levels in neonates. Acta Paediatr Scand, 70:699,.–Two infants were found to have markedly increased TSH levels, 104 and 154 mU/l of plasma, respectively, in a routine screening programme for congenital hypothyroidism. The recall limit used was 50 mU/l of plasma. On follow-up, both infants were clinically euthyroid and had normal serum T₄ and T₃. The elevated TSH levels were confirmed only with some commercial radioimmunoassay kits–but not with others. Similar results were obtained in TSH assays of samples from their mothers, who had no other biochemical or clinical evidence of thyroid dysfunction. Both mothers had intense contact with rabbits over long periods. The apparent TSH activity was found to be associated with the IgG fraction. It was neutralized by the addition of normal rabbit serum to the samples and was caused by antibodies to rabbit immunoglobulin. The activity was eliminated from the circulation of both infants with a half-life of approximately one month. Apparently, the heterophilic antibodies were of maternal origin and were transferred to the foetus via the placenta. Infants with so-called transient hyperthyrotropinaemia identified in screening programmes have to be reevaluated to exclude false TSH elevations of this type.     

Circulating Thyroid Antibodies in Congenital Hypothyroidism

ABSTRACT. The role of maternal thyroid antibodies in congenital hypotyroidism is controversial. We have analysed serum thyroid antibodies in patients and their mothers. In a bioassay, antibodies interacting with thyroid cells were analysed by measuring of TSH-stimulated CAMP production in a rat thyroid cell line, FRTLS. Serum antibodies against the TSH receptor, thyroid peroxidase and thyroglobulin were determined by radioreceptor assay and enzyme-linked immunosorbent assays. The bioassay was performed with IgG preparations from 89 mothers of children with congenital hypothyroidism. Analyses for TSH receptor antibodies and thyroid peroxidase/thyroglobulin antibodies were performed on 144 and 118 sera of newborn patients respectively. No evidence of an increased prevalence of thyroid antibodies was found on comparison with controls. One infant had transient neonatal hyperthyrotropinaemia because of TSH receptor blocking antibodies transferred from the mother. Our data indicate that, apart from transplacental transfer of TSH receptor antibodies, maternal immunoglobulins have a limited role in the aetiology of congenital thyroid dysfunction.     

Hypothyroidism in Children with Filter Paper TSH of 30 to 50 μU/ml at Initial Screening Implication of the TSH Cut-off Point for Recalling of Infants at Risk

ABSTRACT. In a systematic screening of newborns in France daring the period from 1979 to 1983, 959 infants with hypothyroidism were detected. In 16 cases of confirmed hypothyroidism the initial filter paper TSH (FP-TSH) was between 30 and 50 μU/ml. These cases emphasize the necessity of keeping a Y"security zone" for FP-TSH value between 30 and 50 (μU/ml and of recalling these patients for a second test filter paper TSH.     

连云港地区新生儿先天性甲状腺功能减低症及苯丙酮尿症筛查分析

目的 探讨连云港地区新生儿先天性甲状腺功能减退症（CH）及苯丙酮尿症（PKU）发病及分布特征。方法 采集生后72h新生儿155091例足跟血于干血滤纸片上。PKU采用盖氏细菌抑制法测血苯丙氨酸（Phe）水平、CH采用酶联免疫吸附试验（ELISA）或时间分辨荧光免疫法（TRFIA）测促甲状腺素（TSH）作为筛查指标。结果 确诊CH患儿64例，发病率4．126／万（1：2423）：经甲状腺核素显像41例，其中甲状腺异常23例（56％）；64例分布在全市的4县3个城区的45个乡镇（街道），男女性别和城乡发病率均无差异（P均〉0．05），发现1对双胞胎CH患儿；确诊苯丙酮尿症患儿15例，发病率为0．967／万（1：10339）：以上患儿父母未见近亲结婚和显性遗传家族史，母孕期正常，经干预治疗，患儿身体和智力发育与同龄儿比较无显著差异。结论 CH、PKU在连云港地区呈散发性分布，进行新生儿筛查是发现CH、PKU的唯一有效手段。     

Guidelines for Mass Screening of Congenital Hypothyroidism (2014 revision)

Purpose of developing the guidelines: Mass screening for congenital hypothyroidism started in 1979 in Japan, and the prognosis for intelligence has been improved by early diagnosis and treatment. The incidence was about 1/4000 of the birth population, but it has increased due to diagnosis of subclinical congenital hypothyroidism. The disease requires continuous treatment, and specialized medical facilities should make a differential diagnosis and treat subjects who are positive in mass screening to avoid unnecessary treatment. The Guidelines for Mass Screening of Congenital Hypothyroidism (1998 version) were developed by the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology in 1998. Subsequently, new findings on prognosis and problems in the adult phase have emerged. Based on these new findings, the 1998 guidelines were revised in the current document (hereinafter referred to as the Guidelines). Target disease/conditions: Primary congenital hypothyroidism. Users of the Guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, physicians referring patients to pediatric practitioners, general physicians, laboratory technicians in charge of mass screening, and patients.     

Retrospective Analysis of Infants Designated as Positive on Mass-Screening for Congenital Hypothyroidism at Kagoshima University

Mass-screening for congenital hypothyroidism has identified cases of mild hypothyroidism, transient hypothyroidism, and transient hyperthyrotropinemia as well as typical hypothyroidism. In this paper, we examine the clinical data of the cases found positive in the screening test at our hospital. From 1989 to 1999 there were 72 patients with positive screening tests who started levothyroxine sodium (l-T4; Thyradin-S) as supplement therapy. At the age of 3 to 4 yr the patients were re-evaluated to determine whether treatment should be continued. Thyroid scintigraphies were done at the same time. We divided these cases into 4 groups. Those in group 1A started l-T4 in early infancy without a TRH test because of obvious clinical evidence of hypothyroidism, and treatment was continued after re-evaluation (n=37). Those in group 1B also started treatment in early infancy without a TRH test, but treatment was discontinued after re-evaluation (n=20). Patients in group 2A started l-T4 after evaluation by a TRH test and treatment was continued after re-evaluation (n=14), while those in group 2B started treatment after a TRH test, but after re-evaluation, treatment was discontinued (n=1). In group 2A, only a low dose of l-T4 was needed, and a slightly elevated TSH and slightly decreased free T4 (FT4) were observed after the drug washout period. However, these patients had an exaggerated response to the TRH test at re-evaluation. These findings indicate that this group, forming not a small part of whole screening-positive subjects, had mild hypothyroidism. Such patients require careful follow-up and repeated evaluation to determine whether treatment should be continued.     

Monomeric Calcitonin Secretion in Infants with Congenital Hypothyroidism

ABSTRACT. We have determined CT levels in whole serum (iCT) and by an extraction method (exCT) in 25 infants affected by congenital hypothyroidism (CH)–11 athyreotic and 14 dysgenetic–at age 25 days, before the institution of therapy, and at age 2 years. In hypothyroid patients at age 25 days the iCT and exCT levels were similar to those found in controls of the same age. At age 2 years the iCT and exCT levels decreased in both groups of patients. However, whereas the levels of iCTin hypothyroids were similar to those found in controls of the same age, the levels of exCT were significantly lower in hypothyroids than in controls; moreover they were significantly lower in athyreotic than in dysgenetic patients. At this age, after calcium infusion, exCT levels significantly increased in dysgenetic but not in athyreotic patients. We hypothesize that CT deficiency in CH is due to increased degradation of human CT by the substitutive therapy, which, stimulating proteolytic enzymes, destroys the biologic activity of CT. An extraction procedure improves the sensitivity and specificity of the CT assay and it must be used when CT deficiency is suspected. In addition we suggest that the measurement of exCT levels after Ca infusion might be useful to distinguish dysgenetic from athyreotic patients.     

新生儿先天性甲状腺功能低下症的筛查与治疗评估

目的探讨先天性甲状腺功能低下症(甲低)的筛查、治疗方法和随访及疗效评估。方法采用时间分辨荧光免疫法检测滤纸血斑中促甲状腺素(TSH)水平;对召回的可疑患儿,采用化学发光免疫法检测血清甲状腺功能,确诊后予以左甲状腺素钠治疗,正规治疗2~3年后,停药观察,结合甲状腺核素扫描或超声检查、智力测定、骨龄检测及体格检查,进行疗效评估。结果筛查新生儿557 193例,检出甲低339例,发病率1/1644。其中治疗满18个月以上221例(治疗18个月~2年34例、2~3年112例、>3年75例)。甲状腺核素扫描100例,超声检查150例(2项均检查29例):甲状腺异常48例(缺如、异位各8例,发育不良32例);正常173例。发育商>85者98.6%,平均106.5;骨龄发育正常75%,稍落后25%;身高与体质量均达正常。治疗评估:48例确诊为原发性甲低,予终身治疗;173例暂时性甲低,其中86例停药观察,可终止治疗69例,确诊为暂时性甲低;重新恢复治疗9例,确诊为亚临床甲低;继续随访8例。结论开展新生儿疾病筛查,结合安全有效的治疗和规范的随访,完全能预防智残疾病发生和保障儿童体格和智能正常发育。     

Screening for congenital hypothyroidism in Hong Kong

A pilot cord blood TSH screening program for congenital hypothyroidism was commenced in Hong Kong in April 1982. By April 1984, 14 411 neonates born in two hospitals were screened for this disorder. Five cases of primary hypothyroidism and two cases of transient hypothyroidism were detected. The detection of cases of congenital hypothyroidism with only moderately elevated cord blood TSH values means that the recall rate will remain high.     

南京地区1998-2009年新生儿先天性甲状腺功能减低症筛查及治疗随访结果分析

目的 总结并分析1998年1月- 2009年12月南京地区新生儿先天性甲状腺功能减低症(CH)的筛查结果.方法 采集出生72 h新生儿442 454例的足跟血滴于滤纸上,采用时间分辨免疫法测定滤纸血斑促甲状腺激素(TSH),阳性者召回进一步测定静脉血TSH、三碘甲状腺原氨酸(T3)、四碘甲状腺原氨酸(T4)、游离T3(FT3)、游离T4(FT4)以明确诊断.确诊者立即开始予左旋甲状腺素片(4.3～12.0μg·kg-1·d-1)替代治疗,定期监测其甲状腺功能,测量其身高、体质量,其中68例患儿子智力测试,以评估疗效.结果 12 a共筛查442 454人,确诊CH 183例,发病率为0.41‰,对117例进行随访.初始治疗时间的中位数为18 d(7～67d),初始左旋甲状腺素的平均剂量为7.35 μg·kg-1·d-1.CH患儿的身高、体质量结果基本达到正常参照标准.盖泽尔婴幼儿发展量表(GESELL)测试结果显示1例智能发育落后,8例智能发育迟缓.T4、FT4的治疗前水平与患儿的GESELL测试总分、适应性及精细运动均呈正相关(Pa＜0.05).结论 经筛查确诊的CH患儿,应尽可能早地进行激素替代治疗,可有效改善其预后.因此新生儿筛查及随访治疗工作值得推广和完善.     

Genetic Analysis in Children with Transient Thyroid Dysfunction or Subclinical Hypothyroidism Detected on Neonatal Screening

About 30% of children with elevated TSH levels during neonatal screening have a transient form of disorder. On the other hand, it has been reported that subclinical hypothyroidism persists in late childhood in about 30% of children found to be false-positive during neonatal screening. The aim of this study was to determine whether transient thyroid dysfunction and subclinical hypothyroidism detected during neonatal screening are influenced by genetic background. The TSH receptor (TSHR), thyroid peroxidase (TPO) and dual oxidase 2 (DUOX2) genes, for which it has been reported that heterozygous defects cause neonatal transient thyroid dysfunction, were analyzed. Nine children with transient thyroid dysfunction or subclinical hypothyroidism detected during neonatal screening were studied. One child was heterozygous for a TSHR gene mutation (R450H), and another child was heterozygous for a TPO gene mutation (P883S). No children with mutation of the DUOX2 gene were identified. Genetic background may contribute to development of transient thyroid dysfunction and subclinical hypothyroidism detected during neonatal screening.     

先天性甲状腺功能减低症患儿治疗前后血清ghrelin的动态变化

目的 观察甲状腺素替代治疗对先天性甲状腺功能减低症(CH)患儿血清ghrelin水平的影响.方法 研究对象为2007年10月-2008年3月在徐州医学院附属医院确诊并行治疗随访的CH患儿40例及健康体检儿童30例.分组:未治疗组包括甲状腺功能减低的CH患儿20例;治疗组包括新诊断或随访中经甲状腺素片治疗后甲状腺功能正常至少1个月的CH患儿20例;健康对照组年龄、性别相当的健康儿童30例.采用夹心法酶联免疫吸附试验测定3组儿童血清ghrelin水平,采用化学发光法测定三碘甲状腺原氨酸(T3)、四碘甲状腺原氨酸(T4)、促甲状腺激素刺激激素(TSH)水平,同时计算每个样本的体质量指数(BMI)用于相关分析.结果 1.未治疗组ghrelin水平[(2.35±0.23) μg·L-1]虽高于治疗组[(2.16±0.25) μg·L-1]和健康对照组[(1.96±0.27) μg·L-1],但差异无统计学意义(P=0.102).2.Ghrelin与年龄呈负相关(r=-0.325,P<0.05),但与性别、BMI、T3、T4、TSH无相关关系(Pa>0.05).结论 甲状腺激素对中枢或外周ghrelin的产生和分泌可能无调控作用.在不同生长发育时期,不同水平的ghrelin可能有不同的生理作用.     

Thyroid Hormone and Attention in School-Age Children with Congenital Hypothyroidism

The relationship between attention and thyroid hormone was examined using a retrospective database of 85 7-year-old children with congenital hypothyroidism who received psychological evaluations and thyroid function tests on the same day. Four unique subgroups with different levels of thyroxine and thyrotropin were compared on psychological tasks and measures of attention. Children with high levels of both hormones were found to be significantly more distractible on an index of cognitive attention but were reportedly less hyperactive. Level of thyroxine accounted for over 10% of the variance in attention.     

河南省新生儿先天性甲状腺功能低下症筛查及病因调查

目的研究河南省先天性甲状腺功能低下症（甲低,CH）的发病情况及发病原因。方法采用时间分辨免疫荧光法检测1998年1月-2004年12月河南省156家医院非选择性出生的新生儿33.8万例血促甲状腺素（TSH）水平,筛查阳性者召回,用直接化学发光免疫分析法测定其静脉血清T3、T4、TSH水平,以T3、T4低于正常、TSH水平高于正常者确诊为CH患儿,通过对CH患儿及其父母召回进行问卷调查和生长发育、智力测量及相关医学检查,寻找其发病原因及发病的高危因素。结果河南省新生儿CH筛查平均覆盖率5.93%,确诊CH 109例,发病率0.032%。CH患儿109例甲状腺部位正常,发育良好。在有高血压、糖尿病、畸形或智力低下家族史或母孕期有不良情况者中CH发病率较高。结论河南省CH患儿发病可能与甲状腺的缺如和异位无关,可能为激素的合成障碍或受体缺陷所致。     

Comparison of atrophic and goitrous auto-immune thyroiditis in children: Clinical,laboratory and TSH-receptor antibody studies

We studied the clinical features, laboratory and thyroid functions and thyrotropin (TSH)-receptor and thyroid-stimulation antibodies in 21 patients with atrophic auto-immune thyroiditis (AAT) and 48 patients with goitrous auto-immune thyroiditis (GAT) of childhood onset. The clinical features of patient with AAT were cessation of growth and obesity, while asymptomatic enlargement of the thyroid gland was the sole symptom in most patients with GAT. Although the ages at diagnosis were comparable in both groups, the estimated ages at onset were much lower in patients with AAT than in those with GAT. Patients with AAT exhibited more severe hypothyroidism when evaluated by serum thyroxine (T4), tri-iodothyronine (T3), TSH, cholesterol levels and basal metabolic rates. The 24h¹²³I-thyroidal uptake was significantly lower in patients with AAT than in those with GAT. None of the 19 patients with AAT possessed TSH-binding inhibitor immunoglobulins (TBII). On the other hand, 3 of the 32 GAT patients tested, possessed weak to potent TBII activities. Three TBII-positive patients with GAT also possessed thyroid-stimulation blocking antibodies. These findings suggest that: 1. Pathogenesis of AAT in children whose onset of hypothyroidism was before puberty is not due to TSH-receptor blocking antibodies, which are often found in patients with AAT of postpubertal onset. 2. AAT in children is considered not to be due to the later stage of GAT. 3. Some patients with GAT possessed TSH-receptor blocking antibodies. The aetiology and pathogenesis of AAT in children have yet to be elucidated.     

Psychological Development at 7 Years of Age in Children with Congenital Hypothyroidism: Timing and Dosage of Initial Treatment

ABSTRACT. Sixty of 68 consecutive patients detected during the first two years of the Swedish screening programme for congenital hypothyroidism were Griffiths tested at the age 6.5–7.5 years. The test quotients of the patients could not be distinguished from those of reference population. Replacement therapy with 8.7 ± 2.8 μg of l -thyroxine (mean±SD)/kg/d had been started at 15.0 ± 7.1 days of life. Furthermore, normal results on Griffiths tests were also found in 13 patients with delayed normalization of serum TSH, i.e. ≥ 19 mU/l at the age of six weeks, as well as in patients with retarded skeletal maturity and/or very low neonatal serum levels of thyroxine, i.e. < 18 nmol/l and tri-iodothyronine, i.e. <0.92 nmol/l. Our findings indicate that replacement dose of 6–11 μg l -thyroxine/kg/d is adequate and allows normal psychological development if treatment is started early.     

Dissociating Attention Deficits in Children with ADHD and Congenital Hypothyroidism using Multiple CPTs

Recent studies suggest that children with different etiologies of attention disorder also differ as to the types of errors they make on attention tasks. Because these errors are reflective of the core deficits underlying their attention problems, we sought to compare error patterns in children with different attention disorders. Studied were 144 children aged 7–12 years, 43 with attention deficit hyperactivity disorder (ADHD), 35 with congenital hypothyroidism (CH), and 68 controls. Two variations of the continuous performance task (CPT) that differed in demands on inhibitory control and memory were used. One variation, the CPT: A-not-X task, required subjects to observe a continuous stream of letters shown at different rates on the computer screen and respond to all stimuli except "X". The other variation, the CPT: AX task, required them to respond whenever a specified combination of letter such as "A" followed by "X" appeared on the screen. On the CPT:A-not-X task, children with ADHD differed from controls in commission errors, signifying difficulty with inhibitory control, whereas children with CH differed in perceptual sensitivity or signal detection. Although the CH and ADHD groups both performed more poorly than controls on the CPT:AX task, children with CH made more errors to the first stimulus item, suggesting a problem holding information in memory, whereas children with ADHD made more errors to the second item, suggesting impulsivity. These results therefore signify the utility of these tasks in identifying the different mechanisms underlying the specific attention deficits of different groups of children.     

Central Congenital Hypothyroidism Detected by Neonatal Screening in Sapporo, Japan (2000–2004): It’s Prevalence and Clinical Characteristics

In Sapporo, Japan, a neonatal screening program for congenital hypothyroidism (CH) has employed measurement of free thyroxine (T4) and TSH in the same filter-paper blood spot. This system has enabled us to identify primary CH and central CH during the neonatal period. The aim of this study was to clarify the prevalence and clinical characteristics of central CH. For this purpose, the screening program requested serum from infants with free T4 concentrations below the cut off value regardless of the TSH levels. Between January 2000 and December 2004, 83,232 newborns were screened and six central CH patients were detected as a result of follow-up of low free T4 and non-elevated TSH screening (1:13,872). This frequency is higher than in other studies. Four patients showed multiple pituitary hormone deficiency with pituitary malformations on magnetic resonance imaging. One patient was diagnosed as having Prader-Willie syndrome. The remaining patient was considered to have isolated central CH. Our study demonstrated that the frequency of central CH is 1:13,872. Free T4 measurement would also be advantageous in early recognition of multiple pituitary hormone deficiency.