Turner's syndrome and thyroid disease: a transverse study of pediatric patients in Brazil

Might Thyroid Function in Patients with Turner Syndrome Have a Significant Impact on Their Muscle Strength?

Turner syndrome (TS) is a genetic disorder caused by abnormalities in one of the X chromosomes. Individuals with TS have a higher incidence of autoimmune thyroid disorders, particularly Hashimoto's disease, leading to thyroid dysfunction, most commonly hypothyroidism. Hormonal imbalance, growth hormone deficiency, and reduced physical activity contribute to muscle weakness in TS patients, and thyroid dysfunction can exacerbate these effects. The purpose of this study was to evaluate whether thyroid factors affect muscle strength in female patients with TS. The study included 70 women with TS and 88 age- and weight-matched controls. TS diagnoses were genetically confirmed (mosaic karyotypes: n = 20; monosomy X: n = 37; structural abnormalities: n = 7). The main criterion for exclusion from the study was unbalanced thyroid function. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and thyroid antibodies (anti-thyroid peroxidase antibodies (aTPO), anti-thyroglobulin antibodies (aTG)) were measured, and muscle strength was assessed using hand-held dynamometry. In TS patients, higher TSH levels were positively correlated, and higher fT4 levels were negatively correlated with muscle strength. No such correlations were found in controls. Thyroid compensation may impact musculoskeletal health in TS. Lower-normal TSH levels are associated with reduced muscle strength, and autoimmune thyroid changes like aTPO and aTG may contribute to muscle deterioration. Further research is needed to confirm these findings.

Hashimoto's Thyroiditis and Graves' Disease in Genetic Syndromes in Pediatric Age

Autoimmune thyroid diseases (AITDs), including Hashimoto’s thyroiditis (HT) and Graves’ disease (GD), are the most common cause of acquired thyroid disorder during childhood and adolescence. Our purpose was to assess the main features of AITDs when they occur in association with genetic syndromes. We conducted a systematic review of the literature, covering the last 20 years, through MEDLINE via PubMed and EMBASE databases, in order to identify studies focused on the relation between AITDs and genetic syndromes in children and adolescents. From the 1654 references initially identified, 90 articles were selected for our final evaluation. Turner syndrome, Down syndrome, Klinefelter syndrome, neurofibromatosis type 1, Noonan syndrome, 22q11.2 deletion syndrome, Prader–Willi syndrome, Williams syndrome and 18q deletion syndrome were evaluated. Our analysis confirmed that AITDs show peculiar phenotypic patterns when they occur in association with some genetic disorders, especially chromosomopathies. To improve clinical practice and healthcare in children and adolescents with genetic syndromes, an accurate screening and monitoring of thyroid function and autoimmunity should be performed. Furthermore, maintaining adequate thyroid hormone levels is important to avoid aggravating growth and cognitive deficits that are not infrequently present in the syndromes analyzed.

Pediatric endocrinology through syndromes

In everyday practice, a pediatric endocrinologist will face a variety of different endocrine issues (such as short or tall stature, dysthyroidism, abnormal pubertal timing or impaired glucose metabolism), which relevantly contribute to the global care of a number of syndromic conditions. On the other hand, the presence of endocrine features may assist in the diagnostic process, leading to final diagnosis of a syndromic disorder. The intention of this review is to provide a referenced overview of different genetic syndromes characterized by endocrine features, and to present a possible classification, based on whether the endocrinopathy or the syndrome is typically recognized first. Thus, the first part of the manuscript deals with the most common syndromes associated with endocrine dysfunctions, while the second part describes the conditions by which a syndrome is most frequently diagnosed after an endocrine finding. The aim is to provide a practical overview of the assessment of syndromic patients, so that they can be recognized and managed in an integrated, multidisciplinary fashion.

Prevalence of autoimmune thyroid diseases among the Turner Syndrome patients: meta-analysis of cross sectional studies

Objective

This meta-analysis was done to estimate the prevalence of autoimmune thyroid diseases (ATDs) in Turner Syndrome patients, and to determine the clinical status of thyroid autoimmune diseases that occur frequently in association with Turner Syndrome.

Results

A total of 18 studies were included in the meta-analysis. The pooled overall prevalence of autoimmune thyroid diseases in Turner Syndrome patients was 38.6% (95% CI 29.7–47.6%), with 12.7% (95% CI 9.30–16.1%) of them had clinical hypothyroidism and 2.6% (95% CI 1.5–3.8%) had hyperthyroidism. I-squared test had a high result of heterogeneity. In subgroup analyses, the prevalence of ATDs was higher in the European region than Asian region. Autoimmune thyroid diseases are commonly associated with Turner Syndrome. Early detection of thyroid diseases by optimal screening among children with Turner Syndrome is required to ensure effective management.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3950-0) contains supplementary material, which is available to authorized users.

Thyroid Autoimmunity in Girls with Turner Syndrome

Turner syndrome is associated with increased incidence of autoimmune diseases, especially those of the thyroid gland. The aim of this study was to assess the prevalence of thyroid autoimmunity among pediatric patients with Turner syndrome. The study was retrospective and included 41 girls with Turner syndrome aged 6-18 years. Free thyroxine (FT4), thyroid stimulating hormone (TSH), anti-thyroid peroxidase (TPO-Ab) antibodies, anti-thyroglobulin (TG-Ab) antibodies, and karyotype were investigated. The correlation between karyotype and incidence of thyroid autoimmunity was also examined. Eleven patients (26.8%) were positive for TPO-Ab and/or TG-Ab. Three girls from that subgroup were euthyroid, 5 had subclinical hypothyroidism, and 3 were diagnosed with overt hypothyroidism. Out of these 11 patients affected by thyroid autoimmunity, 6 girls had mosaic karyotype with X-isochromosome (n = 4) or with deletions (n = 2), and 5 had the 45,X karyotype. The study findings confirmed a high incidence of thyroid autoimmunity in girls with Turner syndrome, but we failed to observe an association between the incidence of thyroid autoimmunity and karyotype. We conclude that it is important to monitor thyroid function in patients with Turner syndrome because they are prone to develop hypothyroidism.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT ON THYROID DYSFUNCTION CASE FINDING

Hypothyroidism and hyperthyroidism can be readily diagnosed and can be treated in a safe, cost-effective manner. Professional organizations have given guidance on how and when to employ thyroid-stimulating hormone testing for the detection of thyroid dysfunction. Most recently, the United States Preventive Services Task Force did not endorse screening for thyroid dysfunction based on a lack of proven benefit and potential harm of treating those with thyroid dysfunction, which is mostly subclinical disease. The American Association of Clinical Endocrinologists (AACE) is concerned that this may discourage physicians from testing for thyroid dysfunction when clinically appropriate. Given the lack of specificity of thyroid-associated symptoms, the appropriate diagnosis of thyroid disease requires biochemical confirmation. The Thyroid Scientific Committee of the AACE has produced this White Paper to highlight the important difference between screening and case-based testing in the practice of clinical medicine. We recommend that thyroid dysfunction should be frequently considered as a potential etiology for many of the nonspecific complaints that physicians face daily. The application and success of safe and effective interventions are dependent on an accurate diagnosis. We, therefore, advocate for an aggressive case-finding approach, based on identifying those persons most likely to have thyroid disease that will benefit from its treatment.

Clinical practice guidelines for the management of hypothyroidism

INTRODUCTION

Hypothyroidism has long been known for its effects on different organ systems, leading to hypometabolism. However, subclinical hypothyroidism, its most prevalent form, has been recently related to cardiovascular risk and also to maternal-fetal complications in pregnant women.

OBJECTIVES

In these clinical practice guidelines, several aspects of this field have been discussed with the clear objectives of helping physicians treat patients with hypothyroidism, and of sharing some of our Latin American-based clinical experience.

MATERIALS AND METHODS

The Latin American Thyroid Society commissioned a Task Force on Hypothyroidism to develop evidence-based clinical guidelines on hypothyroidism. A systematic review of the available literature, focused on the primary databases of MedLine/PubMed and Lilacs/SciELO was performed. Filters to assess methodological quality were applied to select the best quality studies. The strength of recommendation on a scale from A-D was based on the Oxford Centre for Evidence--based Medicine, Levels of Evidence 2009, allowing an unbiased opinion devoid of subjective viewpoints. The areas of interest for the studies comprised diagnosis, screening, treatment and a special section for hypothyroidism in pregnancy.

RESULTS

Several questions based on diagnosis, screening, treatment of hypothyroidism in adult population and specifically in pregnant women were posed. Twenty six recommendations were created based on the answers to these questions. Despite the fact that evidence in some areas of hypothyroidism, such as therapy, is lacking, out of 279 references, 73% were Grade A and B, 8% Grade C and 19% Grade D.

CONCLUSIONS

These evidence-based clinical guidelines on hypothyroidism will provide unified criteria for management of hypothyroidism throughout Latin America. Although most of the studies referred to are from all over the world, the point of view of thyroidologists from Latin America is also given.

Endocrine autoimmunity in Turner syndrome

BACKGROUND

Turner syndrome is caused by numeric and structural abnormalities of the X chromosome. An increased frequency of autoimmunity as well as an elevated incidence of autoantibodies was observed in Turner patients. The aim of this study was to conduct a retrospective analysis of the incidence of autoimmunity in 66 Italian patients affected by Turner syndrome.

METHODS

Sixty-six unselected and consecutive Italian Turner patients were recruited. The association between age, karyotype and the presence of clinical/pre-clinical autoimmune disorders and of autoantibodies was examined.

RESULTS

Out of the 66 Turner patients, 26 had thyroid autoimmune disorders (39.4%), 14 patients had Hashimoto's thyroiditis with clinical or subclinical hypothyroidism (21.2%) and 12 patients had circulating anti-thyroid antibodies, echographic pattern of diffuse hypoechogenicity and normal thyroid hormone levels (18.2%). None were affected by Graves' disease. We analyzed the overall incidence of thyroid autoimmunity within the 3 different age groups 0-9.9, 10-19.9 and 20-29.9 years. No statistically significant difference was observed in the incidence of thyroid autoimmunity within the age-groups (χ2-test p > 0.05).Out of the 66 patients, 31 patients had the 45,X karyotype; within this first group 14 out of 31 patients were affected by autoimmune thyroid disease. A second group of 29 patients included 19 patients with mosaicism, 5 patients with deletions and 5 patients with ring chromosome; out of these 29 patients 7 were affected by autoimmune thyroid disease. A third group included 6 patients with X isochromosome; 5 out of 6 were affected by autoimmune thyroid disease. A statistically significant difference in the frequency of thyroid autoimmunity within the different karyotype groups was observed (χ2-test p = 0.0173).When comparing the X isochromosome group with the pooled group of other karyotypes, of note, the frequency of thyroid autoimmunity was statistically higher in the X isochromosome group (Fisher exact test p = 0.0315).

CONCLUSIONS

Our data confirm a high frequency of thyroid autoimmunity in Italian Turner patients. Patients with X isochromosome are more prone to develop thyroid autoimmunity. Further, an early assay of autoantibodies and monitoring thyroid hormones is fundamental for detecting hypothyroidism earlier and start adequate replacement therapy.

Rituximab for management of refractory pregnancy-associated immune thrombocytopenic purpura

BACKGROUND

Rituximab is a novel therapy for immune thrombocytopenic purpura (ITP); however, information about its safety in pregnancy is limited. This case illustrates the successful use of rituximab to treat pregnancy-associated ITP.

CASE

A 34-year-old woman presented with severe ITP at 23 weeks' gestation. Standard treatment with corticosteroids, intravenous immune globulin, and splenectomy failed to raise the platelet count. Due to ongoing bleeding, rituximab was given in the 26th week of pregnancy. The platelet count rose to over 100 × 10(9)/L after four weeks. The neonatal B-lymphocyte count normalized at four months after delivery. There were no neonatal complications of rituximab therapy.

CONCLUSION

Rituximab may be safe for use in treating pregnancy-associated ITP. This case highlights the need to investigate further the safety and efficacy of rituximab in pregnancy.

Turner's syndrome and subclinical autoimmune thyroid disease: a two-year follow-up study

Although autoimmune thyroid disease (AITD) is frequent in Turner's syndrome (TS), followup studies are scant, and there are none regarding subclinical thyroiditis. We investigated thyroid function and morphology in 17 patients with TS (mean age 14.6 years) with transient and asymptomatic variations of TSH and/or thyroid hormones. Our 2-year follow-up included measurements of TSH, free T4, T3 and TPO and Tg antibodies, ultrasound (US) (first and last evaluations) and scintigraphy (first evaluation). Thyroid volume was evaluated relative to the patients' stature. Fourteen had abnormal hormones, including four with hypothyroidism and one with hyperthyroidism, ten had positive antibodies, and all had abnormalities on US; uptake was normal in 14/16. Abnormal hormones were independent of antibodies, number of US findings, age, time of disease and volume. At the end of the follow-up, antibodies were associated with a high number of abnormal US features, particularly heterogeneous texture. Our results indicate that recurring thyroid hormone variations in TS are due to chronic AITD.

Dissecting genetic heterogeneity in autoimmune thyroid diseases by subset analysis

Abundant epidemiological data point to a strong genetic susceptibility to the development of autoimmune thyroid diseases (AITD), Graves' disease (GD) and Hashimoto's thyroiditis (HT). However, identifying the AITD susceptibility genes has been confounded by significant genetic heterogeneity that exists in AITD. The goals of the present study were to dissect the genetic heterogeneity in AITD in order to identify novel AITD genes. We studied a dataset of 102 multiplex Caucasian AITD families (540 individuals) and divided them into three subsets: (1) families with young age of onset (AO< or =30), (2) families with females-only affected, and (3) Italian families. These subsets were analyzed separately for linkage with AITD in a whole genome screen. Four subset-specific loci were mapped: analyzing the families with AO< or =30, we identified a locus on 10q (linked with AITD) and a locus on Xp containing the FOXP3 gene (linked with GD); analysis of markers flanking the FOXP3 gene demonstrated association of one of the FOXP3 markers with juvenile GD in females (p=0.02); in the subset of families with females-only affected the thyroglobulin (Tg) gene locus was linked with AITD; and in the Italian subset, a novel locus on 3q was linked with GD. Finally, applying the predivided-sample test confirmed that all four loci were specific to the subsets. We conclude that distinct genes predispose to AITD in different subsets of patients. We have identified four subset-specific AITD loci, and two putative subset-specific AITD susceptibility genes; the FOXP3 gene in juvenile GD and the thyroglobulin gene in females with AITD. In view of the significant genetic heterogeneity observed in AITD, analyzing subsets is an efficient way to resolve heterogeneity and identify novel genes.

Thyroid Epigenetics: X Chromosome Inactivation in Patients with Autoimmune Thyroid Disease

The autoimmune thyroid diseases (AITDs) are female-predominant diseases with a ratio of approximately seven females to each male. X chromosome inactivation (XCI), an epigenetic phenomenon, has been suggested to be skewed in many such female patients with AITD. We analyzed female genomic DNA from 87 patients with Graves' disease (GD), 47 patients with Hashimoto's thyroiditis (HT), and 69 healthy controls. Using an XCI assay based on Hpa II digestion and PCR and DNA sequencing, we found skewed heterozygous XCI (>or=80%) in 20 of 70 GD patients (28.6%) and 11 of 43 HT patients (25.6%), giving a total of 31 of 113 AITD patients (27.4%) with skewed XCI. In contrast, only 5 of 58 healthy controls had skewed XCI (8.6%). Statistical analysis confirmed that XCI skewing was significantly associated with AITD (P = 0.004, OR = 4.0), demonstrating that the degree of XCI is an important contributor to the increased risk of females in developing AITD.

Prevalence of thyroid dysfunction in Turner's syndrome: a long-term follow-up study and brief literature review

Thyroid dysfunction, especially hypothyroidism caused by Hashimoto's thyroiditis is more frequently observed in girls with Turner's syndrome (TS). The aim of the present study was to evaluate prevalence, etiology, karyotype distribution and age at onset of thyroid pathology in girls with TS. Data recorded in 84 girls with TS attending our clinic were analyzed. The mean age +/- standard deviation [SD] at their initial evaluation was 10.3 +/- 3.7 years (range, 0.5 to 19 years) and the mean period of observation was 8.4 +/- 4.4 years. The thyroid function had been evaluated at least once per year in all patients and thyroid autoantibodies (ATA) were available in 51 (60.7%). Hypothyroidism was detected in 24% of the studied subjects and hyperthyroidism in 2.5%. Elevated values of thyroid autoantibodies were detected in 42% of girls with TS, whose ATA had been determined, and 65% had hypothyroidism. Thyroid dysfunction was first noted after the age of 8 years with no difference in the distribution of new cases at the different ages or pubertal stages. There was no difference in the incidence of thyroid dysfunction related to the type of karyotype abnormality. Thyroid dysfunction is more frequently encountered in girls with TS (hypothyroidism: 24% in the total group and 65% in those with positive ATA, hyperthyroidism: 2.5%). Thyroid dysfunction was observed after the age of 8 years with no difference in the occurrence of new cases in the various age groups thereafter. Hence, thyroid function should be evaluated yearly in girls with TS past the age of 8 years and more frequently in those with positive thyroid autoantibodies.

Searching for the autoimmune thyroid disease susceptibility genes: from gene mapping to gene function

The autoimmune thyroid diseases (AITD) are complex diseases that are caused by an interaction between susceptibility genes and environmental triggers. Genetic susceptibility, in combination with external factors (e.g., dietary iodine), is believed to initiate the autoimmune response to thyroid antigens. Abundant epidemiological data, including family and twin studies, point to a strong genetic influence on the development of AITD. Various techniques have been used to identify the genes contributing to the etiology of AITD, including candidate gene analysis and whole genome screening. These studies have enabled the identification of several loci (genetic regions) that are linked with AITD, and in some of these loci putative AITD susceptibility genes have been identified. Some of these genes/loci are unique to Graves' disease (GD) and Hashimoto's thyroiditis (HT), and some are common to both diseases, indicating that there is a shared genetic susceptibility to GD and HT. The putative GD and HT susceptibility genes include both immune modifying genes (e.g., human leukocyte antigen, cytotoxic T lymphocyte antigen-4) and thyroid-specific genes (e.g., TSH receptor, thyroglobulin). Most likely these loci interact, and their interactions may influence disease phenotype and severity. It is hoped that in the near future additional AITD susceptibility genes will be identified and the mechanisms by which they induce AITD will be unraveled.

Health supervision for children with Turner syndrome

This report is designed to assist the pediatrician in caring for the child in whom the diagnosis of Turner syndrome has been confirmed by karyotyping. The report is meant to serve as a supplement to the American Academy of Pediatrics' "Recommendations for Preventive Pediatric Care" and emphasizes the importance of continuity of care and the need to avoid its fragmentation by ensuring a medical home for every girl with Turner syndrome. The pediatrician's first contact with a child with Turner syndrome may occur during infancy or childhood. This report also discusses interactions with expectant parents who have been given the prenatal diagnosis of Turner syndrome and have been referred for advice.