Endocrine Abstracts

Background: Conservation of genes involved in TH transport, metabolism and action can reveal clues about the origins of TH signaling. A deiodinase homologue (DdDio) was previously identified in the social amoeba Dictyostelium discoideum (Singh, 2014). Dictyostelium cells live as single cell amoebae in soil where they feed on bacteria. However, upon starvation a developmental program is initiated that results in the formation of a multicellular fruiti...

Background: Disrupted thyroid hormone (TH) homeostasis has devastating effects on human neurodevelopment. THs are critical signaling molecules in neurodevelopment, acting on differentiation of neural cells, migration, synaptogenesis and myelination, with deiodinases governing intracellular TH concentrations in a spatiotemporal manner. It is remarkable that fetal neural cells, while being key target cells of TH, exhibit strong activity of the TH inactivating enzyme DIO3. Curren...

Background: Postpartum depression (PPD) is a common mental health disorder with a major impact on maternal health and wellbeing and offspring development. Thyroperoxidase antibody (TPOAb) positivity is a major risk factor for postpartum thyroiditis and via this link, it is hypothesized that TPOAb positivity is a risk factor for PPD. However, the results of currently available single center studies are heterogeneous and affected by major study limitations.<p class="abstext"...

Background and Objective: Disrupted thyroid hormone (TH) signaling has devastating effects on human neurodevelopment. The molecular mechanisms underlying TH regulation and action are largely based on animal models. However, animal models are limited in revealing some of the most fundamental aspects of neurodevelopment that are unique to humans. We employed human induced pluripotent stem cell (iPSC) technology to study the effects of T3 on neurodevelopmental processes in a huma...

Background: Resistance to thyroid hormone (TH) beta (RTHβ), caused by mutations in THRB, is characterized by elevated serum (F)T4 accompanied by non-suppressed TSH concentrations. Disease features arise from variable resistance to TH action in tissues expressing Thyroid Hormone Receptor (TR) β (hypothalamus, pituitary, liver) and from thyrotoxic effects in tissues expressing TRα (heart, bone, brain). In symptomatic patients, treatment mainly involves be...

Objectives: During prenatal neurodevelopment, maternal-to-fetal thyroxine (T4) transfer is critical, particularly during the first half of pregnancy when the fetal thyroid gland is immature. Transcellular transport of thyroid hormones (TH) is facilitated by TH transporters. Monocarboxylate transporter 8 (MCT8) is a specific TH transporter that is crucial for transport of TH with a prominent expression at the blood-brain barrier. MCT8 deficiency is a rare disorder consisting of...

Background: MCT8 deficiency is caused by loss-of-function (LoF) mutations in thyroid hormone (TH) transporter MCT8. Patients have developmental delay and abnormal thyroid function tests (TFTs). The large phenotypic variability is not understood. Moreover, phenotypes arising from LoF mutations could be employed to enhance understanding of physiology in the general population. Also, computational disease variant classifiers have poor predictive power to ascertain impact of MCT8 ...

Objectives: Mutations in SECISBP2 cause deficiency of selenoproteins, resulting in a multisystem disorder with abnormal circulating thyroid hormone and selenium levels and features due to lack of specific selenoproteins or loss of antioxidant selenoenzymes. Having observed early-onset, aneurysmal thoracic aortic dilatation in four patients with this disorder, we studied zebrafish and murine Secisbp2 mutant models to determine whether the aortic phenotype and selenopro...

Background: Registries are of key importance for a centre of expertise. Endo-ERN consists of 71 reference centres (RCs) that cover several groups of rare endocrine conditions within 8 themes (www.endo-ern.eu). It is unclear if awareness, participation and availability of registries is uniform for all conditions within Endo-ERN.Objective: To determine the extent of engagement in registries of Endo-ERN members.Methods: Endo-ERN RC le...

Objectives: THRA mutations cause Resistance to Thyroid Hormone α (RTHα), an underdiagnosed disorder with hypothyroid features but near-normal thyroid function tests (TFTs). We developed a pathway, combining molecular analyses, new biomarkers and physiological measurements, to better diagnose and treat this disorder.Methods: Structural and functional analyses of THRA variants, discovered by next generation sequencing in specifi...