High incidence of juvenile Graves' disease in Hong Kong

Longitudinal follow-up of pediatric Graves' disease in preschool children: Clinical characteristics and a case report

RATIONALE

Pediatric Graves' disease at preschool age is a rare condition. Previous reports have indicated that adolescents with this disease are girls. Pediatric Graves' ophthalmopathy in young children is rare, and long-term follow-up reports are lacking.

PATIENT CONCERNS

The patient had hyperthyroidism and bilateral proptosis for 2 years, but she was only 4 years old.

DIAGNOSES

The blood test revealed hyperthyroidism and the ophthalmic examination revealed proptosis. The patient had Graves' disease and Graves' ophthalmopathy.

INTERVENTIONS

Initially, she was followed up in the pediatric department. Bilateral proptosis developed, and she was brought to the ophthalmology department for assistance. Orbital computed tomography revealed borderline enlargement of the extraocular muscles bilaterally. Other initial clinical findings included bilateral upper and lower eyelid trichiasis and mild punctate epithelial erosions of the cornea. She received conservative medical treatment in the ophthalmology department.

OUTCOMES

Remission of hyperthyroidism was achieved 2 years after medical control. No elevated intraocular pressure, strabismus, or optic neuropathy developed during follow-up. Significant cosmetic improvement and gradual resolution of punctate epithelial erosions were found over 10 years. Finally, the patient had only mild bilateral lower trichiasis.

LESSONS

Longitudinal follow-up revealed that the ocular manifestations of proptosis and eyelid trichiasis may have good outcomes. Proptosis gradually improved as the patient grew up.

Increasing Incidence of Juvenile Thyrotoxicosis in Denmark: A Nationwide Study, 1998-2012

AIM

The aim of this study was to determine in a Danish nationwide study whether the incidence rate (IR) of thyrotoxicosis in children below 15 years of age has increased between 1998 and 2012 and to compare the results with previously published national data from 1982 to 1988. Furthermore, we intended to conduct a descriptive study of children diagnosed with Graves' disease (GD) between 2008 and 2012.

METHODS

Children diagnosed with thyrotoxicosis between 1998 and 2012 were identified through the Danish National Patient Registry. All medical records were reviewed to verify the diagnosis. Additional data were collected on children diagnosed with GD in 2008-2012.

RESULTS

In total, 237 patients with juvenile thyrotoxicosis (JT) were identified. The overall IR in 1998-2012 was 1.58/100,000 person-years and has increased significantly from 0.79/100,000 person-years in 1982-1988 (p < 0.001). The IR has continued to increase during the recent 15 years (1.31-1.83/100,000 person-years), with a 12.5% increase with each 5-year time period. The IR increased with age and female sex (p < 0.001). The descriptive study included 79 children with GD, presenting with a wide spectrum of clinical features. Remission occurred in 13.9%.

CONCLUSION

The IR of JT has increased significantly since 1982-1988 and has continued to increase during the recent 15 years. The overall IR was 1.58/100,000 person-years during 1998-2012.

Role of genetic and non-genetic factors in the etiology of Graves' disease

In spite of the advancements in understanding the pathogenic mechanisms of Graves' disease (GD), its ultimate cause remains elusive. The majority of investigators agree that GD is likely a multifactorial disease, due to a complex interplay of genetic and non-genetic factors that lead to the loss of immune tolerance to thyroid antigens and to the initiation of a sustained autoimmune reaction. Twin and family studies support a role of genetic factors, among which the HLA complex, CD40, CTLA-4, PTPN22, FCRL3, thyroglobulin, and the TSH receptor may be involved. Among non-genetic factors, iodine, infections, psychological stress, gender, smoking, thyroid damage, vitamin D, selenium, immune modulating agents, and periods of immune reconstitution may contribute the development of the diseases. Here we review in detail the respective role of genetic and non-genetic factors in the etiology of GD, taking advantage of the great bulk of data generated especially over the past 30 years.

The incidence of autoimmune thyroid disease: a systematic review of the literature

OBJECTIVE

To undertake a systematic review of literature published between 1980 and 2008 on the incidence of autoimmune thyroid disease.

DESIGN

All relevant papers found through searches of Medline, EMBASE and ScienceDirect were critically appraised and an assessment was made of the reliability of the reported incidence data.

RESULTS

The reported incidence of autoimmune hypothyroidism varied between 2.2/100 000/year (males) and 498.4/100 000/year (females) and for autoimmune hyperthyroidism, incidence ranged from 0.70/100 000/year (Black males) to 99/100 000/year (Caucasian females). Higher incidence rates were found in women compared to men for all types of autoimmune thyroid disease. The majority of studies included in the review investigated Caucasian populations mainly from Scandinavia, Spain, the UK and the USA. It is possible that nonautoimmune cases were included in the incidence rates reported here, which would give an overestimation in the incidence rates of autoimmune disease presented.

CONCLUSION

To our knowledge this is the most comprehensive systematic review of autoimmune thyroid disease conducted in the past two decades. Studies of incidence of autoimmune thyroid disease have only been conducted in a small number of mainly western countries. Our best estimates of the incidence of hypothyroidism is 350/100 000/year in women and 80/100 000/year in men; the incidence of hyperthyroidism is 80/100 000/year in women and 8/100 000/year in men.

Thyroid surgery in the tropics

In the tropics thyroid surgery is carried out either by general surgeons or ear, nose and throat surgeons and there are few places with a subspecialist endocrine or head and neck surgeon. The aim of this review is to determine the pattern of thyroid pathology, surgery and surgical outcomes in the tropics. A review of thyroid surgery in tropical regions was carried out based on published articles in English in Medline (1965-2004). The findings are also discussed in the light of the authors' own experience of thyroid disease and thyroid surgery in four continents. The pattern of thyroid pathology varies in the tropics, particularly in regions where endemic goitre is common. Endemic goitre usually regresses with iodine therapy. There is a rising incidence of thyroid autoimmune disease, particularly Graves' disease and Hashimoto's thyroiditis, probably related to an environmental immunological stimulus associated with development. Surgery is indicated for the same reasons as in the developed countries: thyrotoxicosis (more often in the absence of radioactive iodine therapy), solitary thyroid nodule and multinodular or malignant goitre. However, a preoperative cytological diagnosis will only be available in important centres where there is a pathologist. Malignancy appears more prevalent in nodules and goitres in the tropics than in the developed countries, perhaps because patients with malignancy are more likely to be referred to a surgeon. Nonetheless, the evidence suggests that thyroid surgery can be carried out safely with a minimum of complications even in remote mission hospitals with limited facilities for investigation. Standards can be set in terms of surgical outcomes; for example, mortality (0%), permanent recurrent laryngeal nerve (RLN) injury (<2%), re-exploration for haematoma(<2%), permanent hypocalcaemia (<5%) and wound infection (2.5%). The choice of operation depends on the local pathology and the likelihood of being able to obtain lifelong thyroxine. Total thyroidectomy should be avoided whenever possible if thyroxine supplies are unreliable. Advanced thyroid cancer presents a therapeutic challenge and some cases will be unresectable. The management options are limited by the resources available. Similar surgical outcomes should be able to be achieved no matter where the surgery is carried out.

CTLA-4 gene A-G polymorphism and childhood Graves' disease

OBJECTIVE

Graves' disease is associated with a polymorphism at position 49 in exon 1 of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene in Caucasians and Japanese. A high incidence of childhood Graves' disease has been documented in Hong Kong Chinese. The aims of this study were to investigate the CTLA-4 gene A-G polymorphism association in Chinese children with Graves' disease.

PATIENTS AND DESIGN

One hundred and twenty-three Chinese children with Graves' disease (104 girls and 19 boys) and 158 racially matched healthy controls were recruited for the study. Genomic DNA was extracted from venous blood samples. The dimorphism at position 49 A-G was analysed by polymerase chain reaction, single-strand conformation polymorphism and restriction fragment-length polymorphism analysis.

RESULTS

The genotype distribution and allele frequencies of children with Graves' disease differed significantly from those of the controls (P = 0.0023 and P = 0.022, respectively). The presence of at least one G allele (GG or AG) was associated with an increased risk of Graves' disease (OR = 6.8, 95% CI = 2.0-36.1; P = 0.001).

CONCLUSIONS

This study confirms that CTLA-4 49 A-G polymorphism is associated with Graves' disease in Chinese children. The CTLA-4 49 G allele confers an increased risk of childhood Graves' disease.

Increasing incidence of childhood Graves' disease in Hong Kong: a follow-up study

OBJECTIVE

Childhood Graves' disease has been reported to be rare but preliminary epidemiological data on its incidence appeared to be high in Hong Kong Chinese children. The aim of this study is to determine the incidence of childhood Graves' disease in Hong Kong and to analyse whether there is an increasing trend of the incidence.

PATIENTS AND DESIGN

We established a registry of childhood Graves' disease at our centre to collect cases from four districts in Hong Kong. The diagnosis of Graves' disease was based on clinical features, diffused enlargement of thyroid gland, raised free thyroxine or triiodothyronine levels, suppressed TSH levels, and the presence of thyroid receptor antibodies. Confirmed cases of Graves' disease who resided in any of the four districts were used to calculate the incidence for the study period between 1989 and 1998.

RESULTS

One hundred and eighteen Chinese children under 15 years of age had a confirmed diagnosis of Graves' disease during the study period from January 1989 to December 1998. There were 11 boys and 107 girls giving a male to female ratio of 1 : 9.7. The overall incidence rates were 3.2/100 000/year and 6.5/100 000/year for the two periods 1989-93 and 1994-98, respectively. The incidence rates for girls have increased significantly (P < 0.001) from 3.8/100 000/year in 1989 to 14.1/100 000/year in 1998. The current incidence of childhood Graves' disease in our population is about eight times that reported in Danish children.

CONCLUSIONS

This study confirms the high incidence of childhood Graves' disease in Hong Kong and documents an increasing trend for girls. Further studies are required to reveal possible genetic or environmental factors responsible for such epidemiology in Hong Kong Chinese children.

HLA-DRB1*08, DRB1*03/DRB3*0101, and DRB3*0202 are susceptibility genes for Graves' disease in North American Caucasians, whereas DRB1*07 is protective

Graves' disease is known to be HLA-D associated; however, the primary loci involved remain unclear. We examined HLA genotypes of DRB1 and DQB1 plus DRB3 subtypes using PCR-based sequence-specific priming in two groups of North American (Gainesville, FL; and Toronto, Canada) Caucasian patients with Graves' disease. We stratified patients into those with either early age at onset (<20 yr; 13.1 +/- 4.8 yr; n = 30) and later age at onset of disease (38.8 +/- 9.7 yr; n = 62) and compared the results to 192 normal controls. As expected, we found that DRB1*03 was associated with Graves' disease, but at a higher odds ratios for early-onset than later-onset patients (3.7 vs. 2.2). The frequency of DRB1*08 was also increased in both groups of patients, but significantly so only in patients with early-onset Graves' (P = 0.001; chi2 = 10.8). DRB3 was highly associated with Graves' in both groups of patients (P = 0.009; chi2 = 6.83 and P = 0.0015; chi2 = 10.1, respectively); however, the subtypes of DRB3 revealed differential susceptibilities. Whereas the frequencies of both DRB3*0101 and DRB3*0202 were increased over the entire cohort, that of DRB3*0301 was not. Significant P values were found for DRB3*0101 in patients with early-onset and for DRB3*0202 in patients with later onset of Graves' disease. When the haplotypes of DRB1*03-DRB3 of all subtypes were removed for analysis (all DRB1*03 positive also had DRB3*0101), the frequency of DRB3*0202 remained significantly higher in the patients with later onset of Graves' disease than in controls (P = 0.0043; chi2 = 8.13), but DRB3 was no longer positively associated with the early-onset group. In addition, we found that DRB1*07 was negatively associated with both groups of patients (P = 0.024; chi2 = 5.10 and P = 0.0085; chi2 = 6.93). These data suggest that DRB3*0202 is more likely to be the primary susceptible locus than DRB1*03 for patients with later onset of Graves' disease.

The HLA-DQ associations with Graves' disease in Chinese children

OBJECTIVE

Graves' disease has been documented to be associated with different HLA genes in Caucasians and Chinese adults. The incidence of childhood Graves' disease has been reported to be high in Hong Kong Chinese. The aims of this study were to examine the HLA-DQA1 and DQB1 associations with Graves' disease in Chinese children.

PATIENTS AND DESIGN

Sixty-seven Chinese children with Graves' disease (59 girls and 8 boys) and 51 racially matched healthy controls were recruited for the study. Genomic DNA was extracted from venous blood samples. HLA-DQ typings were determined by sequence-specific oligonucleotide probing of the respective enzymatically amplified gene. Frequencies of HLA-DQ alleles at each locus were compared between patients and controls using the chi 2-test.

RESULTS

The frequency of HLA-DQB1.0303 was increased in the combined male and female patient group [53.7%; relative risk (RR) = 4.22; Pc = 0.005] and female patients (50.8%; RR = 3.76; Pc = 0.018) compared with that in the entire control group (21.2%). HLA-DQB1*201 was protective for Graves' disease (10.4%; RR = 0.20; Pc = 0.006). In contrast to studies in Caucasians, DQA1*0501 was not associated with susceptibility for Graves' disease in Chinese children.

CONCLUSIONS

This study confirms that DQB1*0303 is a race-specific susceptible allele for Graves' disease in Chinese. Both susceptible and protective HLA-DQ alleles for Graves' disease in Chinese children are different from those in Caucasians.

The pathogenesis of Graves' disease

Graves' disease, one of the autoimmune thyroid diseases, is caused by the production of IgG autoantibodies directed against the thyrotropin receptor. These antibodies bind to and activate the receptor, causing the autonomous production of thyroid hormones. Despite recent improvements in our understanding of the cellular and molecular basis of autoimmunity, our currently available treatments for Graves' disease have remained largely unchanged over the last 50 years. Nevertheless, new concepts in immune system regulation hold out the prospect in the future for intervention designed to modify, and possibly cure, the underlying disease process.

The significant increase in incidence of Graves' disease in eastern Serbia during the civil war in the former Yugoslavia (1992 to 1995)

The incidence of Graves' disease for the last 25 years in eastern Serbia (Yugoslavia), Timok Region is reported. Registration of all Graves' disease patients was conducted in the Endocrinology-Thyroid Unit of Nuclear Medicine Service, Medical Center Zajecar. Timok Region has a population of 315,000 people in seven counties. From 1971 to 1980 an average of 16 new patients per year were registered; from 1981 to 1990 an average of 33 patients per year were registered; in 1995 the number reached 100, and in 1996 there were 148 newly registered patients. Some of the possible factors influencing this significant annual increase of autoimmune hyperthyroidism are discussed.