The Pathogenic TSH ß-subunit Variant C105Vfs114X Causes a Modified Signaling Profile at TSHR.

1) Background: Central congenital hypothyroidism (CCH) is a rare endocrine disorder that can be caused by mutations in the ß-subunit of thyrotropin (TSHB). The TSHB mutation C105Vfs114X leads to isolated thyroid-stimulating-hormone-(TSH)-deficiency and results in a severe phenotype. The aim of this study was to gain more insight into the underlying molecular mechanism and the functional effects of this mutation based on two assumptions: a) the three-dimensional (3D) structure of TSH should be modified with the C105V substitution, and/or b) whether the C-terminal modifications lead to signaling differences. 2) Methods: wild-type (WT) and different mutants of hTSH were generated in human embryonic kidney 293 cells (HEK293 cells) and TSH preparations were used to stimulate thyrotropin receptor (TSHR) stably transfected into follicular thyroid cancer cells (FTC133-TSHR cells) and transiently transfected into HEK293 cells. Functional characterization was performed by determination of Gs, mitogen activated protein kinase (MAPK) and Gq/11 activation. 3) Results: The patient mutation C105Vfs114X and further designed TSH mutants diminished cyclic adenosine monophosphate (cAMP) signaling activity. Surprisingly, MAPK signaling for all mutants was comparable to WT, while none of the mutants induced PLC activation. 4) Conclusion: We characterized the patient mutation C105Vfs114X concerning different signaling pathways. We identified a strong decrease of cAMP signaling induction and speculate that this could, in combination with diverse signaling regarding the other pathways, accounting for the patient's severe phenotype.

Effects of a combined dietary, exercise and behavioral intervention and sympathetic system on body weight maintenance after intended weight loss: Results of a randomized controlled trial.

BACKGROUND: Lifestyle based weight loss interventions are hampered by long-term inefficacy. Prediction of individuals successfully reducing body weight would be highly desirable. Although sympathetic activity is known to contribute to energy homeostasis, its predictive role in body weight maintenance has not yet been addressed. OBJECTIVES: We investigated, whether weight regain could be modified by a weight maintenance intervention and analyzed the predictive role of weight loss-induced changes of the sympathetic system on long-term weight regain. DESIGN: 156 subjects (age > 18; BMI ≥ 27 kg/m2) participated in a 12-week weight reduction program. After weight loss (T0), 143 subjects (weight loss > 8%) were randomized to a 12-month lifestyle intervention or a control group. After 12 months (T12) no further intervention was performed until month 18 (T18). Weight regain at T18 (regainBMI) was the primary outcome. Evaluation of systemic and tissue specific estimates of sympathetic system was a pre-defined secondary outcome. RESULTS: BMI was reduced by 4.67 ±â€¯1.47 kg/m2 during the initial weight loss period. BMI maintained low in subjects of the intervention group until T12 (+0.07 ±â€¯2.98 kg/m2; p = 0.58 compared to T0), while control subjects regained +0.98 ±â€¯1.93 kg/m2 (p < 0.001 compared to T0). The intervention group regained more weight than controls after ceasing the intervention (1.17 ±â€¯1.34 vs. 0.57 ±â€¯0.93 kg/m2) until T18. Consequently, BMI was not different at T18 (33.49 (32.64; 34.33) vs. 34.18 (33.61; 34.75) kg/m2; p=0.17). Weight loss-induced modification of urinary metanephrine excretion independently predicted regainBMI (R2 = 0.138; p < 0.05). The lifestyle intervention did not modify the course of urinary metanephrines after initial weight loss. CONCLUSIONS: Our lifestyle intervention successfully maintained body weight during the intervention period. However, no long-term effect could be observed beyond the intervention period. Predictive sympathetic activity was not persistently modified by the intervention, which may partially explain the lack of long-term success of such interventions.

Early-Onset Obesity: Unrecognized First Evidence for GNAS Mutations and Methylation Changes.

Context: Early-onset obesity, characteristic for disorders affecting the leptin-melanocortin pathway, is also observed in pseudohypoparathyroidism type 1A (PHP1A), a disorder caused by maternal GNAS mutations that disrupt expression or function of the stimulatory G protein α-subunit (Gsα). Mutations and/or epigenetic abnormalities at the same genetic locus are also the cause of pseudohypoparathyroidism type 1B (PHP1B). However, although equivalent biochemical and radiographic findings can be encountered in these related disorders caused by GNAS abnormalities, they are considered distinct clinical entities. Objectives: To further emphasize the overlapping features between both disorders, we report the cases of several children, initially brought to medical attention because of unexplained early-onset obesity, in whom PHP1B or PHP1A was eventually diagnosed. Patients and Methods: Search for GNAS methylation changes or mutations in cohorts of patients with early-onset obesity. Results: Severe obesity had been noted in five infants, with a later diagnosis of PHP1B due to STX16 deletions and/or abnormal GNAS methylation. These findings prompted analysis of 24 unselected obese patients, leading to the discovery of inherited STX16 deletions in 2 individuals. Similarly, impressive early weight gains were noted in five patients, who initially lacked additional Albright hereditary osteodystrophy features but in whom PHP1A due to GNAS mutations involving exons encoding Gsα was diagnosed. Conclusions: Obesity during the first year of life can be the first clinical evidence for PHP1B, expanding the spectrum of phenotypic overlap between PHP1A and PHP1B. Importantly, GNAS methylation abnormalities escape detection by targeted or genome-wide sequencing strategies, raising the question of whether epigenetic GNAS analyses should be considered for unexplained obesity.

Minireview: Insights Into the Structural and Molecular Consequences of the TSH-ß Mutation C105Vfs114X.

Naturally occurring thyrotropin (TSH) mutations are rare, which is also the case for the homologous heterodimeric glycoprotein hormones (GPHs) follitropin (FSH), lutropin (LH), and choriogonadotropin (CG). Patients with TSH-inactivating mutations present with central congenital hypothyroidism. Here, we summarize insights into the most frequent loss-of-function ß-subunit of TSH mutation C105Vfs114X, which is associated with isolated TSH deficiency. This review will address the following question. What is currently known on the molecular background of this TSH variant on a protein level? It has not yet been clarified how C105Vfs114X causes early symptoms in affected patients, which are comparably severe to those observed in newborns lacking any functional thyroid tissue (athyreosis). To better understand the mechanisms of this mutant, we have summarized published reports and complemented this information with a structural perspective on GPHs. By including the ancestral TSH receptor agonist thyrostimulin and pathogenic mutations reported for FSH, LH, and choriogonadotropin in the analysis, insightful structure function and evolutionary restrictions become apparent. However, comparisons of immunogenicity and bioactivity of different GPH variants is hindered by a lack of consensus for functional analysis and the diversity of used GPH assays. Accordingly, relevant gaps of knowledge concerning details of GPH mutation-related effects are identified and highlighted in this review. These issues are of general importance as several previous and recent studies point towards the high impact of GPH variants in differential signaling regulation at GPH receptors (GPHRs), both endogenously and under diseased conditions. Further improvement in this area is of decisive importance for the development of novel targeted therapies.

A Successful Strategy to Integrate Sex and Gender Medicine into a Newly Developed Medical Curriculum.

BACKGROUND: A new modular, outcome-based, interdisciplinary curriculum was introduced for undergraduate medical education at one of the largest European medical faculties. A key stated institutional goal was to systematically integrate sex and gender medicine and gender perspectives into the curriculum in order to foster adequate gender-related knowledge and skills for future doctors concerning the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and research of diseases. METHODS: A change agent was integrated directly into the curriculum development team to facilitate interactions with all key players of the curricular development process. The gender change agent established a supporting organizational framework of all stakeholders, and developed a 10-step approach including identification, selection, placing relevant sex and gender medicine-related issues in the curricular planning sessions, counseling of faculty members, and monitoring of the integration achieved. RESULTS: With this approach, quantitatively sex and gender medicine-related content was widely integrated throughout all teaching and learning formats and from early basic science to later clinical modules (94 lectures, 33 seminars, and 16 practical courses). Gender perspectives involve 5% of the learning objectives and represent an integral part of the assessment program. Qualitatively, the relevance of gender (sociocultural) differences was combined with sex (biological) differences in disease manifestation throughout the curriculum. CONCLUSIONS: The appointment of a change agent facilitates the development of systematic approaches that can be a key and serve as practice models to successfully integrate new overarching curricular perspectives and dimensions--in this case sex and gender medicine--into a new medical curriculum.

Respiratory alkalosis in children with febrile seizures.

PURPOSE: Febrile seizures (FS) are the most common type of convulsive events in children. FS are suggested to result from a combination of genetic and environmental factors. However, the pathophysiologic mechanisms underlying FS remain unclear. Using an animal model of experimental FS, it was demonstrated that hyperthermia causes respiratory alkalosis with consequent brain alkalosis and seizures. Here we examine the acid-base status of children who were admitted to the hospital for FS. Children who were admitted because of gastroenteritis (GE), a condition known to promote acidosis, were examined to investigate a possible protective effect of acidosis against FS. METHODS: We enrolled 433 age-matched children with similar levels of fever from two groups presented to the emergency department. One group was admitted for FS (n = 213) and the other for GE (n = 220). In the FS group, the etiology of fever was respiratory tract infection (74.2%), otitis media (7%), GE (7%), tonsillitis (4.2%), scarlet fever (2.3%) chickenpox (1.4%), urinary tract infection (1.4%), postvaccination reaction (0.9%), or unidentified (1.4%). In all patients, capillary pH and blood Pco(2) were measured immediately on admission to the hospital. KEY FINDINGS: Respiratory alkalosis was found in children with FS (pH 7.46 ± 0.04, [mean ± standard deviation] Pco(2) 29.5 ± 5.5 mmHg), whereas a metabolic acidosis was seen in all children admitted for GE (pH 7.31 ± 0.03, Pco(2) 37.7 ± 4.3 mmHg; p < 0.001 for both parameters). No FS were observed in the latter group. A subgroup (n = 15; 7%) of the patients with FS had GE and, notably, their blood pH was more alkaline (pH 7.44 ± 0.04) than in the GE-admitted group. During the enrollment period, eight of the patients were admitted on separate occasions because of FS or GE. Consistent with the view that generation of FS requires a genetic susceptibility in addition to acute seizure triggering factors, each of these patients had an alkalotic blood pH when admitted because of FS, whereas they had an acidotic pH (and no FS) when admitted because of GE (pH 7.47 ± 0.05 vs. pH 7.33 ± 0.03, p < 0.005). SIGNIFICANCE: The results show that FS are associated with a systemic respiratory alkalosis, irrespective of the severity of the underlying infection as indicated by the level of fever. The lack of FS in GE patients is attributable to low pH, which also explains the fact that children with a susceptibility to FS do not have seizures when they have GE-induced fever that is associated with acidosis. The present demonstration of a close link between FS and respiratory alkalosis may pave the way for further clinical studies and attempts to design novel therapies for the treatment of FS by controlling the systemic acid-base status.

Gender identity disorders in childhood and adolescence: currently debated concepts and treatment strategies.

INTRODUCTION: Gender identity disorders (GID) can appear even in early infancy with a variable degree of severity. Their prevalence in childhood and adolescence is below 1%. GID are often associated with emotional and behavioral problems as well as a high rate of psychiatric comorbidity. Their clinical course is highly variable. There is controversy at present over theoretical explanations of the causes of GID and over treatment approaches, particularly with respect to early hormonal intervention strategies. METHODS: This review is based on a selective Medline literature search, existing national and international guidelines, and the results of a discussion among experts from multiple relevant disciplines. RESULTS: As there have been no large studies to date on the course of GID, and, in particular, no studies focusing on causal factors for GID, the evidence level for the various etiological models that have been proposed is generally low. Most models of these disorders assume that they result from a complex biopsychosocial interaction. Only 2.5% to 20% of all cases of GID in childhood and adolescence are the initial manifestation of irreversible transsexualism. The current state of research on this subject does not allow any valid diagnostic parameters to be identified with which one could reliably predict whether the manifestations of GID will persist, i.e., whether transsexualism will develop with certainty or, at least, a high degree of probability. CONCLUSIONS: The types of modulating influences that are known from the fields of developmental psychology and family dynamics have therapeutic implications for GID. As children with GID only rarely go on to have permanent transsexualism, irreversible physical interventions are clearly not indicated until after the individual's psychosexual development ist complete. The identity-creating experiences of this phase of development should not be restricted by the use of LHRH analogues that prevent puberty.

Nutrition of very low birth weight infants fed human milk with or without supplemental trace elements: a randomized controlled trial.

BACKGROUND: Very low birth weight infants (<1500 g) have high nutritional needs. Deficiencies of minerals, trace elements (especially zinc) may develop as a result of rapid growth, low body stores and low content of these substances in human milk We hypothesized that fortification of human milk might prevent deficiencies. METHODS: Prospective, randomized trial to evaluate mineral, trace element, thyroid status and growth of infants fed human milk fortified with different amounts of calcium, phosphorus and protein, with (BMF) or without (FM 85) trace elements. Sixty-two infants, 1000 to 1499 g birth weight, were randomized. Minerals and trace elements in serum, red blood cells and human milk and alkaline phosphatase activity, TSH, T4 and FT4 in serum were measured once until the fifth day and at 3 and 6 weeks of life. Clinical course and anthropometric measurements were recorded. RESULTS: Intake of zinc, copper, manganese, calcium, phosphorus and magnesium was higher in the BMF group (P < 0.001). Serum zinc concentrations <0.49 mg/L occurred in 12% of the FM 85 group and 7% of the BMF group at 6 weeks (not significant). Median alkaline phosphatase activity was 436/379 IU/L in the FM 85/BMF group at 6 weeks (P < 0.01). The FM 85 group showed a higher weight gain (P < 0.05), possibly because of higher caloric (P < 0.01) and protein intake (P < 0.05) at 3 weeks. CONCLUSIONS: Zinc deficiency was rare. Elevated intake of calcium, phosphorus and zinc was associated with lower serum alkaline phosphatase activity but did not influence serum zinc concentration.

Thyroid autoimmunity in children and adolescents with type 1 diabetes: a multicenter survey.

OBJECTIVE: To investigate thyroid autoimmunity in a very large nationwide cohort of children and adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Data were analyzed from 17,749 patients with type 1 diabetes aged 0.1-20 years who were treated in 118 pediatric diabetes centers in Germany and Austria. Antibodies to thyroglobulin (anti-TG) and thyroperoxidase (anti-TPO) were measured and documented at least once in 7,097 patients. A total of 49.5% of these patients were boys, the mean age was 12.4 years (range 0.3-20.0 years), and the mean duration of diabetes was 4.5 years (range 0.0-19.5 years). A titer exceeding 100 units/ml or 1:100 was considered significantly elevated. RESULTS: In 1,530 patients, thyroid antibody levels were elevated on at least one occasion, whereas 5,567 were antibody-negative during the observation period. Patients with thyroid antibodies were significantly older (P < 0.001), had a longer duration of diabetes (P < 0.001), and developed diabetes later in life (P < 0.001) than those without antibodies. A total of 63% of patients with positive antibodies were girls, compared with 45% of patients without antibodies (P < 0.001). The prevalence of significant thyroid antibody titers increased with increasing age; the highest prevalence was in the 15- to 20-year age group (anti-TPO: 16.9%, P < 0.001; anti-TG: 12.8%, P < 0.001). Thyroid-stimulating hormone (TSH) levels were higher in patients with thyroid autoimmunity (3.34 microU/ml, range 0.0-615.0 microU/ml) than in control subjects (1.84 microU/ml, range 0.0-149.0 microU/ml) (P < 0.001). Even higher TSH levels were observed in patients with both anti-TPO and anti-TG (4.55 microU/ml, range 0.0-197.0 microU/ml). CONCLUSIONS: Thyroid autoimmunity seems to be particularly common in girls with diabetes during the second decade of life and may be associated with elevated TSH levels, indicating subclinical hypothyroidism.