[Show abstract][Hide abstract] ABSTRACT: Context: Viral/bacterial infection is proposed as a trigger for the autoimmune thyroid diseases (AITD): Graves' disease (GD) and Hashimoto's thyroiditis (HT). Previous studies in European Caucasian AITD subjects found higher birth rates in the autumn/winter, suggesting those born in the autumn/winter experience increased viral/bacterial exposure after birth, impacting upon immune system development and predisposing to AITD later in life. Objective: Month of birth effects were investigated in three independent European Caucasian AITD datasets. Design: Variation in GD and HT onset was compared across months and seasons, with fluctuations across all 12 months analyzed using a Walter-Elwood test. Setting: The study was conducted at a research laboratory. Patients: National UK Caucasian AITD Case Control Collection (2746 GD and 502 HT compared with 1 423 716 UK births), National UK Caucasian GD Family Collection (239 GD and 227 unaffected siblings), and OXAGEN AITD Caucasian Family Collection (885 GD, 717 HT, and 794 unaffected siblings of European Caucasian decent). Main Outcome Measures: Case-control and family-based association studies were measured. Results: No consistent month of birth effects were detected in GD females or males across all three collections. In HT females from the OXAGEN AITD Caucasian Family Collection, slightly higher birth rates were detected in autumn (Walter's test statistic = 7.47, P = .024) however, this was not seen in the HT females from the case-control cohort. Conclusion: Our results suggest in UK/Northern European Caucasian GD subjects, month of birth does not impact on AITD development. Although some month of birth effects for HT females in one collection cannot be excluded, only further work in larger European Caucasian AITD collections can confirm these effects.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: For patients, who remain hypothyroid despite the administration of what would seem adequate doses of levothyroxine, the underlying cause can be difficult to determine. The possibility of a biological cause should first be explored; however, in the majority of cases poor adherence to medication is likely to be the main cause of treatment failure. When non-adherence is suspected but not volunteered, options to confirm the suspicion are limited. In this study we identified patients for whom known drug and pathological causes of levothyroxine malabsorption were excluded and despite often high doses of levothyroxine, the patients remained hypothyroid. DESIGN: Using a weight-determined oral levothyroxine bolus administration, absorption was initially assessed in twenty-three patients. In nearly all patients this was shown to be maximal at 120mins post ingestion. This was then followed by the continued administration of a weekly thyroxine bolus for a four-week period after which TSH and free T4 levels were recorded. RESULTS: All patients showed a rise in free T4 at 120mins following the administration of the levothyroxine bolus, with a mean increase of 54± 3% from baseline. Following the treatment period, using an equivalent weekly levothyroxine dose which was significantly less than that of the daily dose taken by the patients before the test, the TSH reduced from baseline in ~75% of cases. CONCLUSION: Using this combination of tests allows significant malabsorptive problems to be first identified, then potential non-adherence to be demonstrated. A management plan can then be implemented to increase adherence, aiming to improve treatment outcomes.
European Journal of Endocrinology 04/2013; 168(6). DOI:10.1530/EJE-12-1035 · 3.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Common autoimmune disorders tend to coexist in the same subjects and to cluster in families.
We performed a cross-sectional multicenter study of 3286 Caucasian subjects (2791 with Graves' disease; 495 with Hashimoto's thyroiditis) attending UK hospital thyroid clinics to quantify the prevalence of coexisting autoimmune disorders. All subjects completed a structured questionnaire seeking a personal and parental history of common autoimmune disorders, as well as a history of hyperthyroidism or hypothyroidism among parents.
The frequency of another autoimmune disorder was 9.67% in Graves' disease and 14.3% in Hashimoto's thyroiditis index cases (P=.005). Rheumatoid arthritis was the most common coexisting autoimmune disorder (found in 3.15% of Graves' disease and 4.24% of Hashimoto's thyroiditis cases). Relative risks of almost all other autoimmune diseases in Graves' disease or Hashimoto's thyroiditis were significantly increased (>10 for pernicious anemia, systemic lupus erythematosus, Addison's disease, celiac disease, and vitiligo). There was relative "clustering" of Graves' disease in the index case with parental hyperthyroidism and of Hashimoto's thyroiditis in the index case with parental hypothyroidism. Relative risks for most other coexisting autoimmune disorders were markedly increased among parents of index cases.
This is one of the largest studies to date to quantify the risk of diagnosis of coexisting autoimmune diseases in more than 3000 index cases with well-characterized Graves' disease or Hashimoto's thyroiditis. These risks highlight the importance of screening for other autoimmune diagnoses if subjects with autoimmune thyroid disease present with new or nonspecific symptoms.
The American journal of medicine 02/2010; 123(2):183.e1-9. DOI:10.1016/j.amjmed.2009.06.030 · 5.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: New guidance highlights how to do it in primary carePrimary hypothyroidism or underactivity of the thyroid gland is common and is usually managed in primary care.1 In recent years, increasing numbers of patients with and without confirmed thyroid disease have been diagnosed and treated inappropriately using levothyroxine and other thyroid hormones. Management that falls outside good practice as defined nationally and internationally by accredited thyroid experts may compromise patients’ safety. This is potentially an enormous problem, given that in any one year one in four people in the United Kingdom have their thyroid function checked.2 3The Royal College of Physicians, working closely with several specialist professional associations and patient associations with interests in the safe management of thyroid diseases, has recently produced a statement on the diagnosis and management of primary hypothyroidism. This statement sets out clear guidance for general practitioners and the wider medical profession regarding the diagnosis and treatment of primary hypothyroidism in the United Kingdom.3 …
[Show abstract][Hide abstract] ABSTRACT: Both genetic and environmental factors contribute to susceptibility to Graves' disease (GD) and Hashimoto's thyroiditis (HT), as well as disease manifestations.
The objective of the study was to define how endogenous/environmental factors contribute to variation in phenotype.
This was a multicenter cohort study. PATIENTS/OUTCOME MEASURES: We prospectively collected clinical/biochemical data as part of the protocol for a United Kingdom DNA collection for GD and HT. We investigated, in 2805 Caucasian subjects, whether age at diagnosis, gender, family history (FH), smoking history, and presence of goiter influenced disease manifestations.
For 2405 subjects with GD, the presence of goiter was independently associated with disease severity (serum free T4 at diagnosis) (P < 0.001). Free T4 (P < 0.05) and current smoking (P < 0.001) were both independent predictors of the presence of ophthalmopathy. Approximately half of those with GD (47.4% of females, 40.0% of males) and HT (n = 400) (56.4% of females, 51.7% of males) reported a FH of thyroid dysfunction. In GD, a FH of hyperthyroidism in any relative was more frequent than hypothyroidism (30.1 vs. 24.4% in affected females, P < 0.001). In HT, a FH of hypothyroidism was more common than hyperthyroidism (42.1 vs. 22.8% in affected females, P < 0.001). For GD (P < 0.001) and HT (P < 0.05), a FH was more common in maternal than paternal relatives. The reporting of a parent with thyroid dysfunction (hyper or hypo) was associated with lower median age at diagnosis of both GD (mother with hyperthyroidism, P < 0.001) and HT (father with hypothyroidism, P < 0.05). In GD and HT, there was an inverse relationship between the number of relatives with thyroid dysfunction and age at diagnosis (P < 0.01).
Marked associations among age at diagnosis, disease severity, goiter, ophthalmopathy, smoking, and FH provide evidence for interactions between genetic and environmental/endogenous factors; understanding these may allow preventive measures or better tailoring of therapies.
[Show abstract][Hide abstract] ABSTRACT: Propylthiouracil treatment of Graves' disease has been postulated to provoke antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We aimed to investigate whether carbimazole therapy was also associated with increased risk of ANCA.
The occurrence of ANCA and the relationship to thionamide treatment was investigated in a cross-sectional study in a consecutive series of 407 patients' with Graves' disease, 200 with Hashimoto's thyroiditis and 649 normal euthyroid subjects.
ANCA was measured by indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) for proteinase 3 and myeloperoxidase-ANCA.
The prevalence of ANCA, as measured by IIF, was increased in the Graves' disease cohort (19.9%) compared with euthyroid controls (4.6%; P < 0.001). The prevalence of MPO-ANCA (measured by ELISA) was also increased in Graves' disease (P = 0.019). ANCA prevalence was more strongly associated with propylthiouracil treatment than carbimazole (P = 0.0265), although risk of ANCA was also higher in Graves' patients treated with carbimazole than controls (RR 2.2, P < 0.0001). ANCA positivity was not increased in patients with Hashimoto's thyroiditis.
This study revealed a high prevalence of ANCA in treated patients with Graves' disease but not in those with Hashimoto's thyroiditis. Furthermore, within the Graves' disease population, ANCA development was associated with propylthiouracil usage to a greater extent than carbimazole. These findings suggest that the altered immune environment associated with autoimmune thyroid disease is not sufficient to develop ANCA but treatment with thionamides is important in promoting ANCA development.
[Show abstract][Hide abstract] ABSTRACT: Genes and mechanisms involved in common complex diseases, such as the autoimmune disorders that affect approximately 5% of the population, remain obscure. Here we identify polymorphisms of the cytotoxic T lymphocyte antigen 4 gene (CTLA4)--which encodes a vital negative regulatory molecule of the immune system--as candidates for primary determinants of risk of the common autoimmune disorders Graves' disease, autoimmune hypothyroidism and type 1 diabetes. In humans, disease susceptibility was mapped to a non-coding 6.1 kb 3' region of CTLA4, the common allelic variation of which was correlated with lower messenger RNA levels of the soluble alternative splice form of CTLA4. In the mouse model of type 1 diabetes, susceptibility was also associated with variation in CTLA-4 gene splicing with reduced production of a splice form encoding a molecule lacking the CD80/CD86 ligand-binding domain. Genetic mapping of variants conferring a small disease risk can identify pathways in complex disorders, as exemplified by our discovery of inherited, quantitative alterations of CTLA4 contributing to autoimmune tissue destruction.
[Show abstract][Hide abstract] ABSTRACT: It is increasingly apparent that the identification of true genetic associations in common multifactorial disease will require studies comprising thousands rather than the hundreds of individuals employed to date. Using 2,873 families, we were unable to confirm a recently published association of the interleukin 12B gene in 422 type I diabetic families. These results emphasize the need for large datasets, small P values and independent replication if results are to be reliable.
[Show abstract][Hide abstract] ABSTRACT: The cytotoxic T-lymphocyte-associated-4 (CTLA-4) molecule plays an important role in immune regulation by downregulating activation of T cells by antigen-presenting cells. Polymorphisms of the CTLA-4 gene have been shown to be associated with susceptibility to a number of autoimmune diseases. Some, but not all, studies suggest association between the CTLA-4 gene and autoimmune hypothyroidism. The aim of this study was to determine whether allelic association was present between the A-G single nucleotide polymorphism (SNP) at position 49 in exon 1 of the CTLA-4 gene and autoimmune hypothyroidism. The study was performed in 158 patients with autoimmune hypothyroidism and 384 control subjects. All subjects were white Caucasians from the United Kingdom. Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using the restriction enzyme Bbv1. There was a significant excess of the G allele in patients with autoimmune hypothyroidism compared with controls (43% vs. 32% respectively; chi2 = 10.7, p = 0.001; odds ratio 1.57). The GG and the AG genotypes were found to be more frequent in patients with autoimmune hypothyroidism than controls (17% vs. 8.8% and 50% vs. 46% respectively; chi2 = 11.7, p = 0.003). These results suggest that the CTLA-4 gene region on chromosome 2q33 is a susceptibility locus for autoimmune hypothyroidism in the United Kingdom.
[Show abstract][Hide abstract] ABSTRACT: Up to half of patients with Graves' hyperthyroidism have signs of thyroid associated ophthalmopathy, but the factors that cause this disorder are unknown. We investigated two major genetic susceptibility loci for Graves' disease in ophthalmopathy; the MHC class II region and the cytotoxic T lymphocyte antigen-4 (CTLA4) gene. Allelic frequencies of these genes in patients with Graves' disease who did and did not have concurrent thyroid-associated ophthalmopathy did not differ, and are, therefore, unlikely to contribute to its development.
The Lancet 10/2001; 358(9286):984-5. DOI:10.1016/S0140-6736(01)06125-6 · 45.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Graves' disease (GD) is an autoimmune thyroid disease of unknown etiology, although predisposition to the development of this disease is thought to be caused by both genetic and environmental factors. Recently, an association between a promoter polymorphism of the interleukin 4 gene and GD has been reported. A C-T base change at position -590 showed modest protection against the development of GD in a United Kingdom data set of 135 patients with GD and 101 controls. This polymorphism was, therefore, investigated in a much larger case-control cohort of 384 patients with GD and 288 control subjects using PCR, followed by restriction fragment length polymorphism analysis. No protective effect of the T allele of this polymorphism was observed in our data set, and indeed no significant difference in either allelic or genotypic distribution was seen between the patient and control groups. Moreover, calculation of probabilities indicate that the original study lacked sufficient power to support the conclusions drawn. Our data support the hypothesis that the C-T promoter polymorphism of the interleukin 4 gene does not confer protection against the development of GD in Caucasians in the United Kingdom.
[Show abstract][Hide abstract] ABSTRACT: There is little consensus regarding the most appropriate dose regimen for radioiodine (131I) in the treatment of hyperthyroidism. We audited 813 consecutive hyperthyroid patients treated with radioiodine to compare the efficacy of 2 fixed-dose regimens used within our center (185 megabequerels, 370 megabequerels) and to explore factors that may predict outcome. Patients were categorized into 3 diagnostic groups: Graves' disease, toxic nodular goiter, and hyperthyroidism of indeterminate etiology. Cure after a single dose of 131I was investigated and defined as euthyroid off all treatment for 6 months or T4 replacement for biochemical hypothyroidism in all groups. As expected, patients given a single dose of 370 megabequerels had a higher cure rate than those given 185 megabequerels, (84.6% vs. 66.6%, P < 0.0001) but an increase in hypothyroidism incidence at 1 yr (60.8% vs. 41.3%, P < 0.0001). There was no difference in cure rate between the groups with Graves' disease and those with toxic nodular goiter (69.5% vs. 71.4%; P, not significant), but Graves' patients had a higher incidence of hypothyroidism (54.5% vs. 31.7%, P < 0.0001). Males had a lower cure rate than females (67.6% vs. 76.7%, P = 0.02), whereas younger patients (<40 yr) had a lower cure rate than patients over 40 yr old (68.9% vs. 79.3%, P < 0.001). Patients with more severe hyperthyroidism (P < 0.0001) and with goiters of medium or large size (P < 0.0001) were less likely to be cured after a single dose of 131I. The use of antithyroid drugs, during a period 2 wk before or after 131I, resulted in a significant reduction in cure rate in patients given 185 megabequerels 131I (P < 0.01) but not 370 megabequerels. Logistic regression analysis showed dose, gender, goiters of medium or large size, and severity of hyperthyroidism to be significant independent prognostic factors for cure after a single dose of 131I. We have demonstrated that a single fixed dose of 370 megabequerels 131I is highly effective in curing toxic nodular hyperthyroidism as well as Graves' hyperthyroidism. Because male patients and those with more severe hyperthyroidism and medium or large-sized goiters are less likely to respond to a single dose of radioiodine, we suggest that the value of higher fixed initial doses of radioiodine should be evaluated in these patient categories with lower cure rates.
[Show abstract][Hide abstract] ABSTRACT: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare monogenic autoimmune disease with endocrine components including type 1 diabetes, adrenal failure, and thyroid dysfunction, with major autoantibodies directed against adrenal, pancreas, and thyroid tissue. A 13-bp deletion in exon 8 of the autoimmune regulator (AIRE1) gene on chromosome 21q22.3 accounts for more than 70% of mutant alleles in United Kingdom subjects with APECED. To determine whether this polymorphism contributes to disease susceptibility in subjects with autoimmune disease in general, we screened 302 patients with Graves' disease, 154 patients with autoimmune hypothyroidism, 235 patients with type 1 diabetes, and 318 control subjects for the 13-bp deletion of the AIRE1 gene. The mutation was present in only 1 (0.33%) patient with Graves' disease, 1 patient with autoimmune hypothyroidism (0.6%), and 1 (0.315) of the control subjects. No patients with type 1 diabetes were found to carry the mutation. We conclude, therefore, that the 13-bp deletion of the AIRE1 gene is not a susceptibility locus for the more common autoimmune endocrinopathies in the United Kingdom.
[Show abstract][Hide abstract] ABSTRACT: The response to treatment in Graves' hyperthyroidism is unpredictable, and factors postulated to predict outcome have not generally proved clinically useful or been widely adopted in clinical practice. We audited outcome in 536 patients with Graves' hyperthyroidism presenting consecutively to determine whether simple clinical features predict disease presentation and response to treatment. At presentation males had slightly more severe biochemical hyperthyroidism [free T4: males, 64.3 +/- 3.0 pmol/L (mean +/- SE); females, 61.3 +/- 1.7 (P = 0.45); free T3: males, 24.3 +/- 1.5 pmol/L; females, 21.0 +/- 0.6, (P = 0.04)]. Patients less than 40 yr at diagnosis had more severe hyperthyroidism than patients more than 40 yr old [free T4: <40 yr, 64.3 +/- 2.0; >40 yr, 56.7 +/- 2.3 (P = 0.02); free T3: <40 yr, 22.8 +/- 0.8; >40 yr, 19.0 +/- 0.9 (P = 0.003)]. Males had a lower remission rate than females after a course of antithyroid medication [19.6% vs. 40%; odds ratio, 0.37; 95% confidence interval (CI), 0.17-0.79; P < 0.01]. Similarly, patients aged less than 40 yr had a lower remission rate than older patients (32.6% vs. 47.8%; odds ratio, 0.53; 95% CI, 0.32-0.87; P = 0.01). One dose of radioiodine cured hyperthyroidism in fewer males than females (47% vs. 74%; P < 0.0001). Logistic regression analysis demonstrated male sex (odds ratio, 2.80; 95% CI, 1.31-5.98; P = 0.008), serum free T4 concentration at diagnosis (odds ratio, 1.02; 95% CI, 1.0-1.04; P = 0.01), and dose of radioiodine administered (odds ratio, 0.99; 95% CI, 0.99-1.00; P = 0.001) were contributing factors associated with failure to respond to a single dose of radioiodine. As males and younger patients are more likely to fail to respond to medical treatment, and male patients are likewise less likely to respond to a single dose of radioiodine, we suggest that those groups with low remission rates should be offered definitive treatment with radioiodine or surgery soon after presentation and that the value of higher initial doses of radioiodine in males be evaluated.
[Show abstract][Hide abstract] ABSTRACT: Graves' disease and Hashimoto's thyroiditis are organ-specific autoimmune disorders of multifactorial aetiology with a polygenic mode of inheritance. Familial clustering and twin studies provide evidence for a genetic predisposition. Three main approaches have been used in the search for susceptibility loci: population-based case-control studies, classical linkage analysis, and intrafamilial linkage disequilibrium. Case-control studies are a sensitive method of gene detection and the collection of subjects is resource-efficient. However, they require prior knowledge of a candidate gene and are prone to inconsistent results due to false positives that may arise from population mismatch. Linkage analysis is a powerful tool for detecting 'major' genes that does not require a candidate gene and is, therefore, a means of genome screening. This method, however, has limited power to detect genes of 'modest' effect, and the collection of sibpairs and multiple family members may be difficult. Intrafamilial linkage disequilibrium analysis is more sensitive than classical linkage analysis, requires only one affected offspring, and eliminates population mismatch. This approach has confirmed linkage disequilibrium of the HLA region with Graves' disease, previously not detected by linkage analysis. Knowledge of a candidate locus is required, however, and this method cannot, therefore, at present be used for genome screening. It is likely that a combination of all three approaches will be required to identify susceptibility loci for autoimmune thyroid disease.
Journal of Endocrinology 11/1999; 163(1):7-13. DOI:10.1677/joe.0.1630007 · 3.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The large multifunctional proteasome (LMP) molecules are over expressed in thyrocytes, the target cells of Graves' disease, and the LMP genes are found within the MHC class II region. The LMP genes may therefore play a role in susceptibility to Graves' disease. The aim of this this study was to determine whether polymorphisms of the LMP genes, LMP 2 and LMP 7 are in linkage disequilibrium with Graves' disease.
Target DNA was amplified using the polymerase chain reaction. The distribution of an Arg-His polymorphism in the LMP 2 gene and a G/T polymorphism in the LMP 7 gene, both of which lead to the presence of an HhaI restriction site, were investigated in a population based case control and family based study in patients with Graves' disease.
We obtained DNA from 306 patients with Graves' disease and 364 control subjects for the population based case-control study. In an independent family based study, DNA was obtained from 129 families including both parents, an affected sibling with Graves' disease and an unaffected sibling. All families, patients and control subjects were white caucasians.
Frequencies of the alleles and genotypes of the LMP 2 and LMP 7 genes were compared between patients and control subjects using the chi2 test. Transmission of alleles from heterozygous parents to affected and unaffected offspring was assessed using the transmission disequilibrium test (TDT).
In the case control study, no difference in allele or genotype frequency was seen between patients and control subjects at the LMP7 locus. At the LMP2 locus the R allele and the RH genotype were increased in subjects with Graves' disease when compared with control subjects (R allele: 36.3% vs. 29.5%, pc = 0. 0164; RH genotype: 56.5% vs. 45%, pc = 0.0102). However, the R allele was in linkage disequilibrium with the associated HLA DRB1*0304-DQB1*02-DQA1*0501 haplotype, delta = 0.102. Within the family based study, no preferential allelic transmission was seen from heterozygote parents to offspring at either loci.
These results show that association of the LMP 2 locus with Graves' disease is due to linkage disequilibrium with the associated HLA haplotype DRB1*0304-DQB1*02-DQA1*0501.
[Show abstract][Hide abstract] ABSTRACT: Case-control studies suggest that the CTLA-4 gene may be a susceptibility locus for Graves' disease. The previously reported A/G polymorphism at position 49 in exon 1 of the CTLA-4 gene was, therefore, investigated in a case-control (n = 743) and family-based (n = 179) dataset of white Caucasian subjects with Graves' disease. The relationship between CTLA-4 genotype and severity of thyroid dysfunction at diagnosis was also investigated. An increase in frequency of the G (alanine) allele was seen in Graves' patients compared with control subjects (42% vs. 31.5%, respectively; corrected P<0.0002; odds ratio = 1.58), and a significant difference in the distribution of GG, GA, and AA genotypes was observed between the groups (chi2 = 21.7; corrected P<0.00003). Increased transmission of the G allele was seen from heterozygous parents to affected offspring compared to unaffected offspring (chi2 = 5.7; P = 0.025). Circulating free T4 concentrations at diagnosis were significantly associated with CTLA-4 genotype (F = 3.26; P = 0.04). These results support the hypothesis that CTLA-4 may play a role in regulating self-tolerance by the immune system and in the pathogenesis of autoimmune disorders such as Graves' disease.