Exploring the values, preferences, and information needs of patients with NKX2-1-related disorders: A qualitative study protocol

Background: NKX2-1-related disorders have a prevalence of 1:500,000 and are therefore considered a rare condition according to the European Commission's definition. The European Reference Network of Rare Neurological Disorders is developing the first clinical practice guideline on the management of this condition, with the support of the Andalusian Health Technology Assessment Area, Endo-ERN, ERN-Lung and Imegen, within the framework of the ERNs Guidelines programme (DG SANTE/2018/B3/030). Within the scope of this programme, it becomes necessary to explore the patient perspective in order to include it in the ongoing clinical practice guideline and accompanying patient information booklet. Methods and analysis: This study will use qualitative methods to explore the values, preferences and information needs of patient with NKX2-1-related disorders and their caregivers. Participants will come from a variety of countries throughout Europe. One focus group and four semi-structured interviews will be conducted. Pairs will analyse the data using Grounded Theory. The Andalusian Regional Ministry of Health's Ethics Coordinating Committee for Biomedical Research (Sevilla, Andalucía, Spain) has approved this study protocol (29/03/2022). Discussion: This is the first study to explore the values, preferences, and information needs of patients with NKX2-1-related disorders. The proposed study's findings will contribute to the generation of useful knowledge that will provide guidance to improve the care given to patients with the studied condition. While this study will provide valuable insights into the perspectives of patients with NKX2-1-related disorders, the findings are unlikely to be generalizable to patients with other conditions.This study is supported by the European Commission within the contract SANTE/2018/B3/030-SI2.813822 under which the ERNs Guidelines programme is being developed. The funders had and will not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Haploinsufficiency of Dmxl2, Encoding a Synaptic Protein, Causes Infertility Associated with a Loss of GnRH Neurons in Mouse

International audienceCharacterization of the genetic defects causing gonadotropic deficiency has made a major contribution to elucidation of the fundamental role of Kisspeptins and Neurokinin B in puberty onset and reproduction. The absence of puberty may also reveal neurodevelopmental disorders caused by molecular defects in various cellular pathways. Investigations of these neurodevelopmental disorders may provide information about the neuronal processes controlling puberty onset and reproductive capacity. We describe here a new syndrome observed in three brothers, which involves gonadotropic axis deficiency, central hypothyroidism, peripheral demyelinating sensorimotor polyneuropathy, mental retardation, and profound hypoglycemia, progressing to nonautoimmune insulin-dependent diabetes mellitus. High-throughput sequencing revealed a homozygous in-frame deletion of 15 nucleotides in DMXL2 in all three affected patients. This homozygous deletion was associated with lower DMXL2 mRNA levels in the blood lymphocytes of the patients. DMXL2 encodes the synaptic protein rabconnectin-3a, which has been identified as a putative scaffold protein for Rab3-GAP and Rab3-GEP, two regulators of the GTPase Rab3a. We found that rabconnectin-3a was expressed in exocytosis vesicles in gonadotropin-releasing hormone (GnRH) axonal extremities in the median eminence of the hypothalamus. It was also specifically expressed in cells expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) within the pituitary. The conditional heterozygous deletion of Dmxl2 from mouse neurons delayed puberty and resulted in very low fertility. This reproductive phenotype was associated with a lower number of GnRH neurons in the hypothalamus of adult mice. Finally, Dmxl2 knockdown in an insulin-secreting cell line showed that rabconnectin-3a controlled the constitutive and glucose-induced secretion of insulin. In conclusion, this study shows that low levels of DMXL2 expression cause a complex neurological phenotype, with abnormal glucose metabolism and gonadotropic axis deficiency due to a loss of GnRH neurons. Our findings identify rabconectin-3a as a key controller of neuronal and endocrine homeostatic processes

Functional characterization of the novel sequence variant p.S304R in the hinge region of TSHR in a congenital hypothyroidism patients and analogy with other formerly known mutations of this gene portion

Context: Thyroid dysgenesis may be associated with loss-of-function mutations in the thyrotropin receptor (TSHR) gene. Objectives: The aim of this study was to characterize a novel TSHR gene variant found in one patient harboring congenital hypothyroidism (CH) from a cohort of patients with various types of thyroid defects. Materials and methods: This cross-sectional cohort study involved 118 patients with CH and their family members, including 45 with familial and 73 with sporadic diseases. The thyroid gland was normal in 23 patients, 25 patients had hypoplasia, 25 hemithyroid agenesis, 21 had athyreosis, and 21 had ectopy. Genomic DNA was extracted, and 10 exons of the TSHR gene were amplified and sequenced. Mutations in other candidate genes were investigated. Ortholog alignment was performed, and TSHR functional assays were evaluated. Results: We identified one previously unknown missense variation in the hinge region (HinR) of the TSHR gene (p.S304R) in one patient with thyroid hypoplasia. This variant is conserved in our ortholog alignment. However, the p.S304R TSHR variant presented a normal glycosylation pattern and signal transduction activity in functional analysis. Conclusion: We report the ocurrence of a novel nonsynonymous substitution in the HinR of the large N-terminal extracellular domain of the TSHR gene in a patient with thyroid hypoplasia. In contrast with four others in whom TSHR mutations of the hinge portion were previously identified, the p.S304R TSHR variation neither affected TSH binding nor cAMP pathway activation. This TSHR gene variant was documented in a CH patient, but the current data do not support its role in the clinical phenotype

Analysis of ribosome biogenesis factor-modules in yeast cells depleted from pre-ribosomes

Formation of eukaryotic ribosomes requires more than 150 biogenesis factors which transiently interact with the nascent ribosomal subunits. Previously, many pre-ribosomal intermediates could be distinguished by their protein composition and rRNA precursor (pre-rRNA) content. We purified complexes of ribosome biogenesis factors from yeast cells in which de novo synthesis of rRNA precursors was down-regulated by genetic means. We compared the protein composition of these largely pre-rRNA free assemblies with the one of analogous pre-ribosomal preparations by semi-quantitative mass spectrometry. The experimental setup minimizes the possibility that the analysed pre-rRNA free protein modules were derived from (partially) disrupted pre-ribosomal particles and provides thereby strong evidence for their pre-ribosome independent existence. In support of the validity of this approach (i) the predicted composition of the analysed protein modules was in agreement with previously described rRNA-free complexes and (ii) in most of the cases we could identify new candidate members of reported protein modules. An unexpected outcome of these analyses was that free large ribosomal subunits are associated with a specific set of ribosome biogenesis factors in cells where neo-production of nascent ribosomes was blocked. The data presented strengthen the idea that assembly of eukaryotic pre-ribosomal particles can result from transient association of distinct building blocks

Dépistage de l’hypothyroïdie congénitale

International audienceL’hypothyroïdie congénitale est une maladie due à une sécrétion insuffisante d’hormones thyroïdiennes. Les causes sont multiples, mais les plus fréquentes sont dues à une anomalie de développement de la glande thyroïde ou à un trouble de l’hormonosynthèse thyroïdienne. Cette insuffisance thyroïdienne avait jadis des conséquences très graves sur le développement de l’enfant, dues essentiellement à un traitement bien trop tardif du déficit hormonal. Le dépistage néonatal systématique, mis en place depuis plus de 40 ans en France, permet actuellement une prise en charge dès le début de la deuxième semaine après la naissance. Il a transformé le pronostic de l’affection tant sur le plan de la croissance que sur celui du développement intellectuel et de l’insertion socio-professionnelle, qui sont normaux. Une augmentation de l’incidence de la maladie a été rapportée ces dernières années. Elle concerne essentiellement les formes avec glande thyroïde en place. Il est nécessaire de réévaluer la fonction thyroïdienne de ces patients car ces hypothyroïdies peuvent être transitoires

Épidémiologie de l’hypothyroïdie congénitale en France : données récentes

L’hypothyroïdie congénitale (HC) est une maladie liée à une sécrétion insuffisante d’hormone thyroïdienne par la glande thyroïde. Elle peut être en relation soit avec une anomalie de développement de la glande soit avec une glande en place avec ou sans goitre. Le dépistage néonatal systématique mis en place depuis environ 40 ans a permis d’améliorer nos connaissances sur l’épidémiologie de cette maladie rare qui affecte environ une naissance sur 3000. Une augmentation de l’incidence de la maladie a été rapportée ces dernières années. Elle affecte surtout les formes avec glande en place

Aetiology of Hyperthyroidism in Childhood

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Pregnancy outcomes in women with preexisting thyroid diseases: a French cohort study

International audienceWomen with thyroid diseases at the beginning of pregnancy may have suboptimal thyroid hormone levels because of potential difficulties in compensating for the physiological thyroid hormone changes occurring in pregnancy. Our objective was to study the association between pre-existing thyroid diseases, pregnancy complications and neonatal anthropometry. In total, 16,395 women from the ELFE French longitudinal birth cohort were included, and 273 declared pre-pregnancy thyroid diseases. Associations were investigated with multivariable regression models, with adjustment for relevant potential confounders. Body mass index (BMI) was additionally adjusted for in a second stage. As compared with other women, women with pre-pregnancy thyroid diseases were more frequently obese (19.6% vs 9.8%) and had greater odds of gestational diabetes development (OR = 1.58 [95% CI 1.08,2.30]) or had undergone treatment for infertility (OR = 1.57 [95% CI 1.07,2.31]). After adjustment for BMI, the association with gestational diabetes was no longer significant (OR = 1.27 [95% CI 0.86,1.88]). After excluding women with another medical history, those with pre-pregnancy thyroid diseases had increased odds of premature rupture of membranes (OR =1.51 [95% CI 1.01,2.25]). Children born from mothers with hypothyroidism before conception due to a disease or as a potential side effect of treatment had a smaller head circumference at birth than other children (β= -0.23 [95% CI -0.44,-0.01] cm). In conclusion, pre-pregnancy thyroid diseases were associated with risk of infertility treatment, gestational diabetes, and premature rupture of membranes. The association between history of hypothyroidism and moderate adverse effects on fetal head circumference growth needs replication

Early postnatal growth and neurodevelopment in children born moderately preterm or small for gestational age at term: A systematic review.

International audienceA positive association was generally found between EPG and neurodevelopmental outcome for individuals born MP or SGAT. Strategies for future epidemiological studies are suggested to improve the characterisation of this relationship