Common genetic variants associated with thyroid function may be risk alleles for Hashimoto's disease and Graves' disease.

BACKGROUND: Recent studies have identified common genetic variants associated with TSH, free T4 and thyroid peroxidase antibodies, but it is unclear whether these differ between patients with Hashimoto's disease and Graves' disease. OBJECTIVE: To examine whether 11 common genetic variants differ between Graves' disease and Hashimoto's disease. PATIENTS AND MEASUREMENTS: We genotyped 11 common variants in a discovery cohort of 203 Australian patients with autoimmune thyroid disease (AITD). Two variants with significant or suggestive associations were analysed in a replication cohort of 384 Danish patients. RESULTS: For rs753760 (PDE10A), the minor allele frequency in Graves' disease and Hashimoto's disease was 0·38 vs. 0·23, respectively, (P = 6·42 × 10-4 ) in the discovery cohort, 0·29 vs. 0·24 (P = 0·147) in the replication cohort and 0·32 vs. 0·24 in combined analysis (P = 0·0021; all analyses adjusted for sex). In healthy controls from Busselton, the frequency was 0·29, significantly different from Hashimoto's disease but not Graves' disease. For rs4889009 (MAF gene region), the frequency of the minor G-allele in Graves' disease and Hashimoto's disease was 0·48 vs. 0·36 (P = 0·0156) in the discovery cohort, 0·48 vs. 0·34 (P = 1·83 × 10-4 ) in the replication cohort and 0·48 vs. 0·35 in the combined analysis (P = 7·53 × 10-6 ); in controls, the frequency was 0·38, significantly different from Graves' disease but not Hashimoto's disease. After further adjustment for smoking, associations with rs4889009 remained significant, whereas those with rs753760 were not. CONCLUSION: Common variants in PDE10A and MAF gene regions may influence whether patients with AITD develop Graves' disease or Hashimoto's disease.

Genome-wide association identifies three new susceptibility loci for Paget's disease of bone.

Paget's disease of bone (PDB) is a common disorder characterized by focal abnormalities of bone remodeling. We previously identified variants at the CSF1, OPTN and TNFRSF11A loci as risk factors for PDB by genome-wide association study. Here we extended this study, identified three new loci and confirmed their association with PDB in 2,215 affected individuals (cases) and 4,370 controls from seven independent populations. The new associations were with rs5742915 within PML on 15q24 (odds ratio (OR) = 1.34, P = 1.6 × 10(-14)), rs10498635 within RIN3 on 14q32 (OR = 1.44, P = 2.55 × 10(-11)) and rs4294134 within NUP205 on 7q33 (OR = 1.45, P = 8.45 × 10(-10)). Our data also confirmed the association of TM7SF4 (rs2458413, OR = 1.40, P = 7.38 × 10(-17)) with PDB. These seven loci explained ∼13% of the familial risk of PDB. These studies provide new insights into the genetic architecture and pathophysiology of PDB.

Small changes in thyroxine dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life: results of a double-blind, randomized clinical trial.

CONTEXT: In patients with primary hypothyroidism, anecdotal evidence suggests that well-being is optimized by fine adjustment of T(4) dosage, aiming for a serum TSH concentration in the lower reference range. This has not been tested in a clinical trial. OBJECTIVE: Our objective was to test whether adjustment of T(4) dosage aiming for a serum TSH concentration less than 2 mU/liter improves well-being compared with a serum TSH concentration in the upper reference range. DESIGN: We conducted a double-blind, randomized clinical trial with a crossover design. PARTICIPANTS: Fifty-six subjects (52 females) with primary hypothyroidism taking T(4) (>/=100 microg/d) with baseline serum TSH 0.1-4.8 mU/liter participated. INTERVENTIONS: Each subject received three T(4) doses (low, middle, and high in 25-microg increments) in random order. OUTCOME MEASURES: Outcome measures included visual analog scales assessing well-being (the primary endpoint) and hypothyroid symptoms, quality of life instruments (General Health Questionnaire 28, Short Form 36, and Thyroid Symptom Questionnaire), cognitive function tests, and treatment preference. RESULTS: Mean (+/- sem) serum TSH concentrations were 2.8 +/- 0.4, 1.0 +/- 0.2, and 0.3 +/- 0.1 mU/liter for the three treatments. There were no significant treatment effects on any of the instruments assessing well-being, symptoms, quality of life, or cognitive function and no significant treatment preference. CONCLUSIONS: Small changes in T(4) dosage do not produce measurable changes in hypothyroid symptoms, well-being, or quality of life, despite the expected changes in serum TSH and markers of thyroid hormone action. These data do not support the suggestion that the target TSH range for the treatment of primary hypothyroidism should differ from the general laboratory range.

Are Australian children iodine deficient? Results of the Australian National Iodine Nutrition Study.

OBJECTIVE: To document the population iodine nutritional status in Australian schoolchildren. DESIGN AND SETTING: Cross-sectional survey of schoolchildren aged 8-10 years, based on a one-stage random cluster sample drawn from all Year 4 school classes in government and non-government schools in the five mainland Australian states of New South Wales, Victoria, South Australia, Western Australia and Queensland. The study was conducted between July 2003 and December 2004. PARTICIPANTS: 1709 students from 88 schools (881 boys and 828 girls), representing 85% of the estimated target number of students. The class participation rate was 65%. MAIN OUTCOME MEASURES: (i) Urinary iodine excretion (UIE) levels (compared with the criteria for the severity of iodine deficiency of the World Health Organization/International Council for the Control of Iodine Deficiency Disorders: iodine replete, UIE > or = 100 microg/L; mild iodine deficiency, UIE 50-99 microg/L; moderate iodine deficiency, UIE 20-49 microg/L; severe iodine deficiency, UIE < 20 microg/L); (ii) Thyroid volumes measured by ultrasound (compared with new international reference values). RESULTS: Overall, children in mainland Australia are borderline iodine deficient, with a national median UIE of 104 microg/L. On a state basis, NSW and Victorian children are mildly iodine deficient, with median UIE levels of 89 microg/L and 73.5 microg/L, respectively. South Australian children are borderline iodine deficient, with a median UIE of 101 microg/L. Both Queensland and Western Australian children are iodine sufficient, with median UIE levels of 136.5 microg/L and 142.5 microg/L, respectively. Thyroid volumes in Australian schoolchildren are marginally increased compared with international normative data obtained from children living in iodine sufficient countries. There was no significant association between UIE and thyroid volume. CONCLUSION: Our results confirm the existence of inadequate iodine intake in the Australian population, and we call for the urgent implementation of mandatory iodisation of all edible salt in Australia.

Combined thyroxine/liothyronine treatment does not improve well-being, quality of life, or cognitive function compared to thyroxine alone: a randomized controlled trial in patients with primary hypothyroidism.

T(4) is standard treatment for hypothyroidism. A recent study reported that combined T(4)/liothyronine (T(3)) treatment improved well-being and cognitive function compared with T(4) alone. We conducted a double-blind, randomized, controlled trial with a crossover design in 110 patients (101 completers) with primary hypothyroidism in which liothyronine 10 micro g was substituted for 50 micro g of the patients' usual T(4) dose. No significant (P < 0.05) difference between T(4) and combined T(4)/T(3) treatment was demonstrated on cognitive function, quality of life scores, Thyroid Symptom Questionnaire scores, subjective satisfaction with treatment, or eight of 10 visual analog scales assessing symptoms. For the General Health Questionnaire-28 and visual analog scales assessing anxiety and nausea, scores were significantly (P < 0.05) worse for combined treatment than for T(4) alone. Serum TSH was lower during T(4) treatment than during combined T(4)/T(3) treatment (mean +/- SEM, 1.5 +/- 0.2 vs. 3.1 +/- 0.2 mU/liter; P < 0.001), a potentially confounding factor; however, subgroup analysis of subjects with comparable serum TSH concentrations during each treatment showed no benefit from combined treatment compared with T(4) alone. We conclude that in the doses used in this study, combined T(4)/T(3) treatment does not improve well-being, cognitive function, or quality of life compared with T(4) alone.