Case of Resistance to Thyroid hormones (RTH) with relatively rare mutation in Thyroid Hormones Receptor (THR)

This is an article that share clinical manifestation and diagnosis of patient with THR mutation, who found to have very rare mutation in THR-beta.

Hypercholesterolemia in Two Siblings with Resistance to Thyroid Hormones Due to Disease-Causing Variant in Thyroid Hormone Receptor (THRB) Gene

Resistance to thyroid hormone beta (RTHβ) is a syndrome characterized by a reduced response of target tissues to thyroid hormones. In 85% of cases, a pathogenic mutation in the thyroid hormone receptor beta (THRB) gene is found. The clinical picture of RTHβ is very diverse; the most common findings are goiter and tachycardia, but the patients might be clinically euthyroid. The laboratory findings are almost pathognomonic with elevated free thyroxin (fT4) levels and high or normal thyrotropin (TSH) levels; free triiodothyronin (fT3) levels may also be elevated. We present three siblings with THRB mutation (heterozygous disease-variant c.727C>T, p.Arg243Trp); two of them also had hypercholesterolemia, while all three had several other clinical characteristics of RTHβ. This is the first description of the known Slovenian cases with RTHβ due to the pathogenic mutation in the THRB gene. Hypercholesterolemia might be etiologically related with RTHβ, since the severity of hormonal resistance varies among different tissues and hypercholesterolemia in patients with THRB variants might indicate the relatively hypothyroid state of the liver. We suggest that cholesterol levels are measured in all RTHβ patients.

Central Resistance to Thyroid Hormones in Morbidly Obese Subjects Is Reversed after Bariatric Surgery-Induced Weight Loss

Endocrine abnormalities are common in obesity, including altered thyroid function. The altered thyroid function of obesity may be due to a mild acquired resistance to the thyroid hormone. The aim of this study was to investigate the effect of weight loss after bariatric surgery (BS) on resistance to thyroid hormones in patients with extreme obesity compared with a control group. We performed an observational study evaluating patients with extreme obesity who underwent BS. We included 106 patients (83 women) and 38 controls (24 women). The primary endpoint was the thyrotroph thyroxine resistance index (TT4RI) and thyroid stimulating hormone (TSH) index (TSHRI). The parameters were studied before and after surgery. TSHRI and TT4RI were higher in the obese patients than in the control group. TT4RI and TSHI decreased significantly over time after surgery, with this decrease being associated with the excessive body mass index (BMI) loss and C-reactive protein (CRP). In extreme obesity, BS promotes a significant decrease in the increased TT4RI and TSHI. This decrease of TT4RI and TSHI is progressive over time after BS and significantly associated with excess BMI lost and CRP. Extreme obesity is characterized by a mild reversible central resistance to thyroid hormones.

A Rare Case of Partial Peripheral Thyroid Hormone Resistance Due to a Point Mutation in the Membrane Integrin Α(V)Β(3) and Concomitant Hashimoto`s Thyroiditis

BACKGROUND: Peripheral resistance to thyroid hormones is a type of unresponsiveness of the peripheral cells or tissues to FT3 and/or FT4. Generalised resistance to thyroid hormones affects the pituitary gland and most of the peripheral tissues. Selective pituitary resistance or central resistance to thyroid hormones include unresponsiveness of the pituitary gland, but the peripheral tissues are responsive. Selective peripheral resistance involves peripheral tissue or cellular resistance to thyroid hormones, but the pituitary gland is responsive.CASE PRESENTATION: We present a rare case of a female patient with partial peripheral resistance to thyroid hormones due to a point mutation coding for the beta subunit of the integrin molecule α(V)β(3) and concomitant Hashimoto`s thyroiditis. Clinically, the patient`s symptoms were in favour of hypothyroidism, and the laboratory results were in favour of the secondary hyperthyroid state. PCR protein amplification detected a point mutation coding for the membrane receptor, which mediates a signal via the MAPK pathway when bonded with thyroid hormones.CONCLUSION: Peripheral resistance to thyroid hormones is a very rare condition and can often be misdiagnosed due to the broad spectrum of clinically similar differential diagnostic entities. Molecular analysis is required to confirm the exact underlying cause for the impaired peripheral sensitivity to thyroid hormones syndrome.