Thyroid hormone resistance and large goiter mimicking infiltrative carcinoma in a pediatric patient.

OBJECTIVES: Resistance to thyroid hormone (RTH) is a genetic condition, caused by mutations in the thyroid hormone receptor gene and characterized by impaired end organ responsiveness to thyroid hormone. Here we describe a novel case of THR associated with large goiter mimicking infiltrative c. CASE PRESENTATION: A 13-year-old male with a hyperthyroid phenotype of RTH diagnosed as a toddler, on methimazole and nadolol therapies presented with an increase in goiter size and possible nodule. Thyroid ultrasound was concerning for a diffuse infiltrative process or malignancy. Methimazole was discontinued and he underwent further imaging, fine needle aspiration and core biopsies. Biopsy results were reassuring and imaging findings were subsequently attributed to RTH rather than malignancy. He started every other day liothyronine therapy, which led to a decrease in goiter size, thyroglobulin level, and improvement of hyperthyroid symptoms. CONCLUSIONS: This is the first case to our knowledge describing the above thyroid imaging findings in association with RTH. It also adds important information to the pediatric literature regarding management of the hyperthyroid phenotype of RTH, including the role of liothyronine therapy.

Diagnosis of Resistance to Thyroid Hormone due to a Rare Mutation in the Thyroid Hormone Receptor Beta Gene in a Patient Previously Presumed to Have Graves' Disease.

Clinicians may confuse an impaired sensitivity to thyroid hormone with hyperthyroidism and offer an inappropriate treatment. We report a diagnosis of resistance to thyroid hormone (RTH) caused by a rare mutation in the thyroid hormone receptor beta gene in a patient previously presumed to have Graves' disease. We have found only one published case of a novel point mutation, c.749T>C (p.Ile250Thr variant) associated with 50% reduction in thyroid hormone receptor binding affinity for triiodothyronine in the I250T mutant; it was found in this patient. A 66-year-old male veteran, with a history of non-ischemic cardiomyopathy and arrhythmias, was referred by a cardiologist with concerns for a possible thyrotropin (TSH) adenoma on account of elevated TSH and free thyroxine (FT4) levels. Pituitary imaging was negative. He was previously treated with radioiodine for presumptive Graves' disease in the civilian sector. Examination revealed a goiter with no nodules. Repeat TSH and FT4 levels were elevated and also free triiodothyronine (FT3) and reverse triiodothyronine. These findings and other test results were consistent with RTH, which was confirmed by genetic testing. Mutation analysis showed the patient to be heterozygous for the p.Ile250Thr variant. He later developed hypothyroidism. Resistance to thyroid hormone can be misdiagnosed as hyperthyroidism with consequent inappropriate treatment. Treatment is not needed in most RTH-beta patients. Thyroid ablation should generally be avoided. Clinicians must be cautious whenever they encounter concurrent elevation of TSH, FT4, and FT3. This RTH-beta patient has a rare I250T mutant of the thyroid hormone receptor beta gene, the second reported case in the literature.

The clinical characteristics and gene mutations associated with thyroid hormone resistance syndrome coexisting with pituitary tumors.

Aims: Resistance to thyroid hormone (RTH) and pituitary tumors are both rare diseases, and the differential diagnosis of these two diseases is difficult in some cases. There are also patients who have both conditions, making diagnosis more difficult. To better understand this aspect, we analyzed the clinical characteristics and gene mutations of RTH coexisting with pituitary tumors. Methods: Database retrieval was conducted in the PubMed, Cochrane Library, and SinoMed databases, and the search contents were case reports or case series of patients with RTH coexisting with pituitary tumors. The demographic, clinical manifestations, and imaging characteristics of pituitary tumors and gene mutations were summarized. Results: Thirteen articles involving 16 patients with RTH coexistent with pituitary tumors, consisting of 13 female patients, one male patient, and two patients with unknown sex, were included. The patients were 10 to 79 years old and most patients were 41-55 years old (43.75%). The 16 patients were from seven different countries and three continents (Asia, the Americas, and Europe). All the patients showed an abnormal secretion of TSH, and five patients underwent transsphenoidal surgery. Finally, four patients were pathologically confirmed to have TSHoma. A total of 11 different mutations occurred at nine amino acid sequence sites (251, 310, 344, 347, 383, 429, 435, 438, and 453). Two different mutations occurred in both the no. 435 and no. 453 amino acid sequences. Fourteen patients provided their treatment histories, and all had undergone different treatment regimens. Conclusions: Patients with both RTH and pituitary tumors had multiple clinical manifestations and different thyroid functions, imaging characteristics of pituitary tumors, genetic mutations of THRß, and treatments. However, due to the limited number of cases, the patients were mainly women. Further studies with more cases that focus on the mechanism are still needed.

Atrial Fibrillation with Heart Failure in a Case with Resistance to Thyroid Hormone Due to a Rare Thyroid Hormone Receptor ß Gene Mutation.

Resistance to thyroid hormone (RTH) is a rare disease typically associated with elevated levels of thyroid hormones and non-suppressed thyroid stimulating hormones. The most common cause of RTH is thyroid hormone receptor ß (THRß) gene mutation. Most individuals with RTH are considered clinical euthyroid. We report a family with a rare heterozygous point mutation, c.959G>T, (p.R320L) of the THRß gene. The proband developed atrial fibrillation and life-threatening heart failure with pulmonary edema, which was quite different from previously reported THRß gene mutations. Considering the rareness of RTH and the heterogeneity of its phenotypes, our report allows for a better understanding of the manifestation and management of patients with RTH and THRß gene mutation.

[Thyroxine replacement therapy in patients with thyroid cancer and thyroid hormone resistance syndrome]. / Terapia sostitutiva tiroxinica in pazienti affetti da carcinoma tiroideo e sindrome di resistenza agli ormoni tiroidei.

Resistance to thyroid hormone (RTH) is a genetic syndrome defined by an impaired sensitivity to thyroid hormones. It is characterized by discrepancies between the blood levels of thyroid hormones (FT3, FT4) and TSH, and by the coexistence of hypothyroidism and hyperthyroidism symptoms. Here we describe the case of a patient affected with thyroid cancer and RTH in whom it was difficult to obtain a good control of TSH after total thyroidectomy despite high doses of thyroxine replacement therapy. This represents a unique model to improve the understanding of the alterations in the feedback mechanism in patients with RTH and to optimize the replacement therapy in patients with concomitant thyroid cancer who need adequate TSH control.

Autoimmune thyroid disease and thyroid function test fluctuations in patients with resistance to thyroid hormone.

OBJECTIVE: Resistance to thyroid hormone beta (RTHß) is an inherited syndrome caused by mutations in the thyroid hormone receptor ß (THRB) gene. Patients with RTHß typically have elevated thyroid hormone levels with non-suppressed serum thyroid-stimulating hormone (TSH). We aimed to elucidate the clinical, laboratory, and imaging findings of RTHß patients and further to explore their association with THRB gene mutations. DESIGN AND METHODS: We retrospectively reviewed the clinical charts and compared the clinical findings of 68 RTHß patients (45 probands and 23 relatives) and 30 unaffected relatives in Kuma Hospital. RESULTS: Genetic testing revealed 35 heterozygous THRB gene mutations. Among all RTHß patients, autoimmune thyroid disease (AITD) was detected in 42.1% of men and 40.9% of women, showing that the prevalence of AITD in affected males was significantly higher than in unaffected relatives (P = 0.019). During the follow-up of 44 patients, 13 patients (29.5%; 8 (42.1%) with AITD and 5 (20%) without AITD) temporarily showed thyroid function test results inconsistent with RTHß. Two patients with the R383H mutation, which has little dominant-negative effect, temporarily showed normal thyroid hormone and TSH levels without AITD. CONCLUSIONS: The frequency of AITD in male RTHß patients was significantly higher compared to unaffected relatives. More than 20% of RTHß patients temporarily showed laboratory findings atypical of RTHß during their follow-up, and patients with AITD and specific THRB mutations were prone to display such findings. Therefore, genetic testing should be performed even for patients with fluctuations in thyroid function test results to avoid misdiagnosis and inappropriate treatment.

Persistent COUP-TFII expression underlies the myopathy and impaired muscle regeneration observed in resistance to thyroid hormone-alpha.

Thyroid hormone signaling plays an essential role in muscle development and function, in the maintenance of muscle mass, and in regeneration after injury, via activation of thyroid nuclear receptor alpha (THRA). A mouse model of resistance to thyroid hormone carrying a frame-shift mutation in the THRA gene (THRA-PV) is associated with accelerated skeletal muscle loss with aging and impaired regeneration after injury. The expression of nuclear orphan receptor chicken ovalbumin upstream promoter-factor II (COUP-TFII, or Nr2f2) persists during myogenic differentiation in THRA-PV myoblasts and skeletal muscle of aged THRA-PV mice and it is known to negatively regulate myogenesis. Here, we report that in murine myoblasts COUP-TFII interacts with THRA and modulates THRA binding to thyroid response elements (TREs). Silencing of COUP-TFII expression restores in vitro myogenic potential of THRA-PV myoblasts and shifts the mRNA expression profile closer to WT myoblasts. Moreover, COUP-TFII silencing reverses the transcriptomic profile of THRA-PV myoblasts and results in reactivation of pathways involved in muscle function and extracellular matrix remodeling/deposition. These findings indicate that the persistent COUP-TFII expression in THRA-PV mice is responsible for the abnormal muscle phenotype. In conclusion, COUP-TFII and THRA cooperate during post-natal myogenesis, and COUP-TFII is critical for the accelerated skeletal muscle loss with aging and impaired muscle regeneration after injury in THRA-PV mice.

Cardiac complications of thyroid hormone resistance syndromes.

Thyroid hormones exert their action by binding to their thyroid hormone receptors among other mechanisms. They are involved in different cardiac functions, including contractility and rhythm. The mutation of thyroid hormone receptor ß is the main cause of thyroid hormone resistance. The cardiac phenotype of mutated patients has been studied in several cohorts of patients with different mutations. Tachycardia, palpitation and cardiac arrhythmia frequently appear; atrial flutter/fibrillation is found in up to 20%. Cardiac systolic and diastolic functions are impaired compared to hyperthyroid or euthyroid subjects, but cases of heart failure have not been reported. No correlation between genotype and cardiac phenotype has been found. Patients with a mutation of thyroid hormone receptor α frequently present bradycardia and systolic and diastolic functions that are similar to those of hypothyroid subjects. Levothyroxine treatment partly improves these parameters.

Patients with mutations of the Thyroid hormone beta-receptor show an ADHD-like phenotype for performance monitoring: an electrophysiological study.

Resistance to thyroid hormone beta (RTHß) is a syndrome of reduced responsiveness of peripheral tissue to thyroid hormone, caused by mutations in the thyroid hormone receptor beta (THRB). Its cognitive phenotype has been reported to be similar to attention deficit hyperactivity disorder (ADHD). This study used electrophysiological biomarkers of performance monitoring in RTHß to contribute further evidence on its phenotypical similarity to ADHD. Twenty-one participants with RTHß aged 18-67 years and 21 matched healthy controls performed a modified flanker task during EEG recording. The RTHß and control groups were compared on behavioural measures and components of event related potentials (ERPs), i.e. the error related negativity (ERN), the error positivity (Pe) and P3 component. There were no significant group differences with regard to behaviour. RTHß subjects displayed significantly reduced ERN and Pe amplitudes compared to the controls in the response-locked ERPs. In addition, we observed reduced P3 amplitudes in both congruent and incongruent trials, as well as prolonged P3 latencies in RTHß subjects in the stimulus-locked ERPs. Our findings reveal alterations in error detection and performance monitoring of RTHß patients, likely indicating reduced error awareness. The electrophysiological phenotype of RTHß subjects with regard to action monitoring is indistinguishable from ADHD.

Two Mutations in Thyroid Hormone Receptor Beta Gene (P453A and C36Y) in a Family with Resistance to Thyroid Hormone with Comorbid Myotonic Dystrophy.

The co-occurrence of resistance to thyroid hormone beta (RTHß) and myotonic dystrophy type 1 (DM1) was observed in a Japanese family. Two mutations, P453A and C36Y, were identified in the thyroid hormone receptor beta (THRB) gene. Whereas family members with THRBP453A exhibited RTHß, two members with THRBC36Y but without THRBP453A had normal thyroid function. Two members, one with RTHß and the other without, had a triplet expansion in the dystrophia myotonia protein kinase gene, a hallmark of DM1. The member with both RTHß and DM1 developed atrial fibrillation at the age of 16 years, suggesting a synergistic impact on the heart.

Impaired Sensitivity to Thyroid Hormones Is Associated With Diabetes and Metabolic Syndrome.

OBJECTIVE: Diabetes prevalence and incidence increase among individuals with hypothyroidism but also among those with hyperthyroxinemia, which seems contradictory. Both high free thyroxine (fT4) and high thyroid-stimulating hormone (TSH) are present in the resistance to thyroid hormone syndrome. A mild acquired resistance to thyroid hormone might occur in the general population and be associated with diabetes. We aimed to analyze the association of resistance to thyroid hormone indices (the Thyroid Feedback Quantile-based Index [TFQI], proposed in this work, and the previously used Thyrotroph T4 Resistance Index and TSH Index) with diabetes. RESEARCH DESIGN AND METHODS: We calculated the aforementioned resistance to thyroid hormone indices based on a U.S. representative sample of 5,129 individuals ≥20 years of age participating in the 2007-2008 National Health and Nutrition Examination Survey (NHANES). Also, to approximate TFQI, a U.S.-referenced Parametric TFQI (PTFQI) can be calculated with the spreadsheet formula =NORM.DIST(fT4_cell_in_pmol_per_L,10.075,2.155,TRUE)+NORM.DIST(LN(TSH_cell_in_mIU_per_L),0.4654,0.7744,TRUE)-1. Outcomes of interest were glycohemoglobin ≥6.5%, diabetes medication, diabetes-related deaths (diabetes as contributing cause of death), and additionally, in a fasting subsample, diabetes and metabolic syndrome. Logistic and Poisson regressions were adjusted for sex, age, and race/ethnicity. RESULTS: Odd ratios for the fourth versus the first quartile of TFQI were 1.73 (95% CI 1.32, 2.27) (P trend = 0.002) for positive glycohemoglobin and 1.66 (95% CI 1.31, 2.10) (P trend = 0.001) for medication. Diabetes-related death rate ratio for TFQI being above versus below the median was 4.81 (95% CI 1.01, 22.94) (P trend = 0.015). Further adjustment for BMI and restriction to normothyroid individuals yielded similar results. Per 1 SD in TFQI, odds increased 1.13 (95% CI 1.02, 1.25) for diabetes and 1.16 (95% CI 1.02, 1.31) for metabolic syndrome. The other resistance to thyroid hormone indices showed similar associations for diabetes-related deaths and metabolic syndrome. CONCLUSIONS: Higher values in resistance to thyroid hormone indices are associated with obesity, metabolic syndrome, diabetes, and diabetes-related mortality. Resistance to thyroid hormone may reflect energy balance problems driving type 2 diabetes. These indices may facilitate monitoring treatments focused on energy balance.

Resistance to thyroid hormone ß in autoimmune thyroid disease: a case report and review of literature.

BACKGROUND: Resistance to thyroid hormone beta (RTHß) results in symptoms of both increased and decreased thyroid hormone action. The effect of thyroid hormone changes in different types of autoimmune thyroid disease (AITD) in RTHß is dynamic. CASE PRESENTATION: A 25-year-old Asian female had a RTHß Y321C mutation with Hashimoto's thyroiditis and type 2 diabetes mellitus. She was followed-up through gestation and two years postpartum, revealing development of postpartum thyroiditis (PPT) with characteristic wide fluctuations in serum thyrotropin levels, and of spontaneous recovery from an episode of transient hypothyroidism. The presence of RTHß did not prolong thyroiditis duration nor progressed toward permanent hypothyroidism. Prenatal genetic analysis was not performed on the unaffected fetus, and did not result in congenital hypothyroidism, possibly because maternal free thyroxine (FT4) levels were mildly elevated at less than 50% above the reference range in early gestation and gradually decreased to less than 20% after the 28th gestational week. CONCLUSION: In RTHß patients with autoimmune thyroid disease, episodes of thyroid dysfunction can significantly alter thyrotropin levels. During pregnancy, mildly elevated maternal free thyroxine levels less than 20% above the upper limit may not be harmful to unaffected fetuses. Unnecessary thyroid hormone control and fetal genetic testing was avoided during the gestational period with monthly follow-up.

[Clinical characteristics of thyroid hormone resistance syndrome in two cases with different subtypes].

Objective: To analyze the clinical characteristics of children with two types of thyroid hormone resistance (RTH) syndrome, and to detect the variants of thyroid hormone receptor alpha(TRα) and TRß gene in children. Method: Two children with RTH were reported in regard to clinical manifestation, laboratory examination and genetic variants. Some related reports in literature were reviewed. Result: Case 1 was a girl, 10 years old, with thyroid enlargement for several days and without thyrotoxicosis. Laboratory work-up revealed that free thyroxine (FT(4)) was 65.77 pmol/L (reference 12-22) , free triiodothyronine (FT(3)) was 15.36 pmol/L (reference 3.1-6.8) and thyroid stimulating hormone (TSH) level was normal. There was a likely pathogenic missense variant detected in TRß gene and this patient was diagnosed with RTHß. Case 2 was a boy, 3 years old, with classic features of hypothyroidism(growth retardation, developmental retardation, skeletal dysplasia) but had only borderline-abnormal thyroid hormone levels. Targeted sequencing showed a de novo heterozygous nonsense variant in TRα gene which is a pathogenic variant and this patient been diagnosed with RTHα. Conclusion: Thyroid enlargement is a common clinical manifestation of RTHß, with laboratory work-up reveals elevated FT(4) and FT(3) levels but TSH level is normal. The clinical manifestations of RTHα are similar to those of hypothyroidism, but the thyroid hormone levels are almost normal. The gene sequence and the pathogenicity analysis for TRα and TRß will help to make a definitive diagnosis.

Hypothyroidism associated with parathyroid disorders.

Hypothyroidism may occur in association with congenital parathyroid disorders determining parathyroid hormone insufficiency, which is characterized by hypocalcemia and concomitant inappropriately low secretion of parathormone (PTH). The association is often due to loss of function of genes common to thyroid and parathyroid glands embryonic development. Hypothyroidism associated with hypoparathyroidism is generally mild and not associated with goiter; moreover, it is usually part of a multisystemic involvement not restricted to endocrine function as occurs in patients with 22q11 microdeletion/DiGeorge syndrome, the most frequent disorders. Hypothyroidism and hypoparathyroidism may also follow endocrine glands' damages due to autoimmunity or chronic iron overload in thalassemic disorders, both genetically determined conditions. Finally, besides PTH deficiency, hypocalcemia can be due to PTH resistance in pseudohypoparathyroidism; when hormone resistance is generalized, patients can suffer from hypothyroidism due to TSH resistance. In evaluating patients with hypothyroidism and hypocalcemia, physical examination and clinical history are essential to drive the diagnostic process, while routine genetic screening is not recommended.

Coexistence of resistance to thyroid hormone and ectopic thyroid: ten-year follow-up

SUMMARY Resistance to thyroid hormone (RTH) coexisting with ectopic thyroid is rare. Here we report a case of RTH with ectopic thyroid. A ten-year-old girl had been misdiagnosed as congenital hypothyroidism and treated with levothyroxine since she was born. Ten-year follow-up showed that the elevated thyrotropin was never suppressed by levothyroxine and no signs indicating hyperthyroidism or hypothyroidism despite elevated FT3 and FT4 levels. Therefore the girl developed no defects in physical and cognitive development. Pituitary adenoma was excluded by magnetic resonance imaging. Ultrasonography did not find the thyroid gland in the normal place, while the thyroid scan found a large lingual thyroid gland. The octreotide inhibition test showed a reduction in thyrotropin by 41.98%. No mutation was detected in the thyroid hormone receptor (THR) β, THRα, thyrotropin receptor (TSHR), and GNAS1 genes. To our knowledge, it is an interesting RTH case coexisting with lingual thyroid.

A Novel Thyroid Hormone Receptor Beta Gene Mutation (G251V) in a Thai Patient with Resistance to Thyroid Hormone Coexisting with Pituitary Incidentaloma.

A patient is reported with resistance to thyroid hormone beta caused by a novel THRB gene mutation and coexisting pituitary microadenoma. A 41-year-old Thai woman presented with elevated serum thyroid hormone levels and non-suppressed thyrotropin (TSH). Magnetic resonance imaging showed a 4 mm × 2 mm pituitary adenoma. Five of her relatives had similar thyroid tests abnormalities, but a sister had Graves' disease. Thyroperoxidase and thyroglobulin antibodies were positive in all affected family members, except for the proband's 4.5-year-old niece. Lack of thyrotoxic symptoms and TSH suppression by triiodothyronine indicated incidentaloma rather than a TSH-secreting pituitary adenoma. Genetic analysis revealed a THRB gene mutation (c.1037G>T), resulting in p.G251V.

Resistance to Thyroid Hormone Complicated with Type 2 Diabetes and Cardiomyopathy in a Patient with a TRß Mutation.

Resistance to thyroid hormone (RTH) is a genetic disorder characterized by reduced tissue responsiveness to thyroid hormone. We herein describe a 60-year old man who presented with the clinical features of cardiomyopathy, diabetes mellitus and elevated thyroid hormones with unsuppressed thyroid stimulating hormone. A genetic analysis of thyroid hormone receptor (TR) revealed a missense mutation (A268D) in the TRß gene. Clinical manifestations of RTH may be variable due to different tissue distributions of TR subtypes and different actions of mutant receptors. The current case demonstrates that patients with a TRß mutation may have impaired his glucose metabolism and a reduced cardiac function, although patients appear clinically euthyroid.

Coexistence of resistance to thyroid hormone and ectopic thyroid: ten-year follow-up.

Resistance to thyroid hormone (RTH) coexisting with ectopic thyroid is rare. Here we report a case of RTH with ectopic thyroid. A ten-year-old girl had been misdiagnosed as congenital hypothyroidism and treated with levothyroxine since she was born. Ten-year follow-up showed that the elevated thyrotropin was never suppressed by levothyroxine and no signs indicating hyperthyroidism or hypothyroidism despite elevated FT3 and FT4 levels. Therefore the girl developed no defects in physical and cognitive development. Pituitary adenoma was excluded by magnetic resonance imaging. Ultrasonography did not find the thyroid gland in the normal place, while the thyroid scan found a large lingual thyroid gland. The octreotide inhibition test showed a reduction in thyrotropin by 41.98%. No mutation was detected in the thyroid hormone receptor (THR) ß, THRα, thyrotropin receptor (TSHR), and GNAS1 genes. To our knowledge, it is an interesting RTH case coexisting with lingual thyroid.

Thyroid hormone resistance in two patients with papillary thyroid microcarcinoma and their BRAFV600E mutation status.

Resistance to thyroid hormone (RTH) is a rare autosomal dominant hereditary disorder. Here in, we report two patients with RTH in whom differentiated thyroid cancer was diagnosed. Two patients were admitted to our clinic and their laboratory results were elevated thyroid hormone levels with unsuppressed TSH. We considered this situation thyroid hormone resistance in the light of laboratory and clinical datas. Thyroid nodule was palpated on physical examination. Thyroid ultrasonography showed multiple nodules in both lobes. Total thyroidectomy was performed. The pathological findings were consistent with papillary thyroid microcarcinoma. BRAFV600E mutation analysis results were negative. RTH is very rare and might be overlooked. There is no consensus on how to overcome the persistently high TSH in patients with RTH and differentiated thyroid cancer (DTC). Further studies are needed to explain the relationship between RTH and DTC which might be helpful for the treatment of these patients.