Genetic architecture of congenital hypogonadotropic hypogonadism: insights from analysis of a Portuguese cohort.

STUDY QUESTION: What is the contribution of genetic defects in Portuguese patients with congenital hypogonadotropic hypogonadism (CHH)? SUMMARY ANSWER: Approximately one-third of patients with CHH were found to have a genetic cause for their disorder, with causal pathogenic and likely pathogenic germline variants distributed among 10 different genes; cases of oligogenic inheritance were also included. WHAT IS KNOWN ALREADY: CHH is a rare and genetically heterogeneous disorder characterized by deficient production, secretion, or action of GnRH, LH, and FSH, resulting in delayed or absent puberty, and infertility. STUDY DESIGN SIZE DURATION: Genetic screening was performed on a cohort of 81 Portuguese patients with CHH (36 with Kallmann syndrome and 45 with normosmic hypogonadotropic hypogonadism) and 263 unaffected controls. PARTICIPANTS/MATERIALS SETTING METHODS: The genetic analysis was performed by whole-exome sequencing followed by the analysis of a virtual panel of 169 CHH-associated genes. The main outcome measures were non-synonymous rare sequence variants (population allele frequency <0.01) classified as pathogenic, likely pathogenic, and variants of uncertain significance (VUS). MAIN RESULTS AND THE ROLE OF CHANCE: A genetic cause was identified in 29.6% of patients. Causal pathogenic and likely pathogenic variants were distributed among 10 of the analysed genes. The most frequently implicated genes were GNRHR, FGFR1, ANOS1, and CHD7. Oligogenicity for pathogenic and likely pathogenic variants was observed in 6.2% of patients. VUS and oligogenicity for VUS variants were observed in 85.2% and 54.3% of patients, respectively, but were not significantly different from that observed in controls. LARGE SCALE DATA: N/A. LIMITATIONS REASONS FOR CAUTION: The identification of a large number of VUS presents challenges in interpretation and these may require reclassification as more evidence becomes available. Non-coding and copy number variants were not studied. Functional studies of the variants were not undertaken. WIDER IMPLICATIONS OF THE FINDINGS: This study highlights the genetic heterogeneity of CHH and identified several novel variants that expand the mutational spectrum of the disorder. A significant proportion of patients remained without a genetic diagnosis, suggesting the involvement of additional genetic, epigenetic, or environmental factors. The high frequency of VUS underscores the importance of cautious variant interpretation. These findings contribute to the understanding of the genetic architecture of CHH and emphasize the need for further studies to elucidate the underlying mechanisms and identify additional causes of CHH. STUDY FUNDING/COMPETING INTERESTS: This research was funded by the Portuguese Foundation for Science and Technology (grant numbers PTDC/SAU-GMG/098419/2008, UIDB/00709/2020, CEECINST/00016/2021/CP2828/CT0002, and 2020.04924.BD) and by Sidra Medicine-a member of the Qatar Foundation (grant number SDR400038). The authors declare no competing interests.

Diabetes and Stroke: Impact of Novel Therapies for the Treatment of Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is a significant risk factor for stroke. Nevertheless, the evidence supporting stringent glycemic control to reduce macrovascular complications, particularly stroke, is not as clear as for microvascular complications. Presently, risk reduction strategies are based on controlling multiple risk factors, including hypertension, dyslipidemia, glycemia, smoking, and weight. Since 2008, new pharmacological therapies for treating T2DM have been required to undergo trials to ensure their cardiovascular safety. Remarkably, several novel therapies have exhibited protective effects against the combined endpoint of major cardiovascular events. Evidence from these trials, with stroke as a secondary endpoint, along with real-world data, suggests potential benefits in stroke prevention, particularly with glucagon-like peptide 1 receptor agonists. Conversely, the data on sodium-glucose cotransporter type 2 inhibitors remains more controversial. Dipeptidyl peptidase 4 inhibitors appear neutral in stroke prevention. More recent pharmacological therapies still lack significant data on this particular outcome. This article provides a comprehensive review of the evidence on the most recent T2DM therapies for stroke prevention and their impact on clinical practice.

A serious and unusual presentation of congenital isolated ACTH deficiency due to TBX19 mutation, beyond the neonatal period.

Summary: Congenital isolated adrenocorticotrophic hormone (ACTH) deficiency due to T-box transcription factor-19 (TBX19 mutation) (MIM 201400; ORPHA 199296) usually presents in the neonatal period with severe hypoglycemia, seizures, and sometimes prolonged cholestatic jaundice. We report a case with an unusual presentation that delayed the diagnosis. A 9-month-old female patient with no relevant personal history was admitted to the emergency department due to a hypoglycemic seizure in the context of acute gastroenteritis. There was rapid recovery after glucose administration. At age 4, she presented with tonic-clonic seizures, fever, and gastrointestinal symptoms and came to need support in an intensive care unit. Low serum cortisol was documented and hydrocortisone was initiated. After normalization of inflammatory parameters, the patient was discharged with hydrocortisone. The genetic investigation was requested and compound heterozygous mutations in TBX19 were detected. This is a rare case of presentation of TBX19 mutation outside the neonatal period and in the setting of acute disease, which presented a diagnostic challenge. Learning points: Congenital isolated adrenocorticotrophic hormone deficiency due to TBX19 mutation usually presents with neonatal hypoglycemia and prolonged cholestatic jaundice. An uneventful neonatal period, however, does not exclude the diagnosis as the disease may be asymptomatic at this stage. In the context of idiopathic hypoglycemia, even in the context of acute disease, hypocortisolism must always be excluded. Genetic evaluation should be performed in cases of congenital central hypocortisolism to allow proper counselling.

The Mysterious Universe of the TSH Receptor.

The thyroid-stimulating hormone receptor (TSH-R) is predominantly expressed in the basolateral membrane of thyrocytes, where it stimulates almost every aspect of their metabolism. Several extrathyroidal locations of the receptor have been found including: the pituitary, the hypothalamus, and other areas of the central nervous system; the periorbital tissue; the skin; the kidney; the adrenal; the liver; the immune system cells; blood cells and vascular tissues; the adipose tissue; the cardiac and skeletal muscles, and the bone. Although the functionality of the receptor has been demonstrated in most of these tissues, its physiological importance is still a matter of debate. A contribution to several pathological processes is evident in some cases, as is the case of Grave's disease in its multiple presentations. Conversely, in the context of other thyroid abnormalities, the contribution of the TSH-R and its ligand is still a matter of debate. This article reviews the several different sites of expression of the TSH-R and its potential role in both physiological and pathological processes.

Vitamin D and Autoimmune Thyroid Disease-Cause, Consequence, or a Vicious Cycle?

Vitamin D is a steroid hormone traditionally connected to phosphocalcium metabolism. The discovery of pleiotropic expression of its receptor and of the enzymes involved in its metabolism has led to the exploration of the other roles of this vitamin. The influence of vitamin D on autoimmune disease-namely, on autoimmune thyroid disease-has been widely studied. Most of the existing data support a relationship between vitamin D deficiency and a greater tendency for development and/or higher titers of antibodies linked to Hashimoto's thyroiditis, Graves' disease, and/or postpartum thyroiditis. However, there have also been some reports contradicting such relationships, thus making it difficult to establish a unanimous conclusion. Even if the existence of an association between vitamin D and autoimmune thyroid disease is assumed, it is still unclear whether it reflects a pathological mechanism, a causal relationship, or a consequence of the autoimmune process. The relationship between vitamin D's polymorphisms and this group of diseases has also been the subject of study, often with divergent results. This text presents a review of the recent literature on the relationship between vitamin D and autoimmune thyroid disease, providing an analysis of the likely involved mechanisms. Our thesis is that, due to its immunoregulatory role, vitamin D plays a minor role in conjunction with myriad other factors. In some cases, a vicious cycle is generated, thus contributing to the deficiency and aggravating the autoimmune process.