DLG2 mutations in the etiology of pubertal delay and Idiopathic Hypogonadotropic Hypogonadism

Introduction: Idiopathic Hypogonadotropic hypogonadism (IHH) is caused by dysfunction of the hypothalamic-pituitary-gonadal axis. DLG2 was recently implicated as a gene associated with delayed puberty and which may also contribute to IHH. The confirmation of the candidate puberty genes in independent IHH cohorts has become crucial due to the lack proper genotype phenotype segregations in reported pedigrees. Therefore, we aimed to screen DLG2 in patients variants in a large cohort of IHH patients. Methods: The present study included a total of 336 IHH patients from 290 independent families. The coding and flanking regions of the DLG2 were screened for potentially important variants in the WES data. Candidate variants were evaluated in the gnomAD and GME databases according to their allele frequencies, and only those with a frequency <0.0001 were considered rare. Detected variants were classified according to the ACMG/AMP criteria. Results: We found one homozygous and two heterozygous missense variants in three independent pedigrees. Identified variants were found extremely rare or not reported in gnomAD. Two variants were categorized as “uncertain significance” the other one was “likely pathogenic” according to the ACMG criteria. All patients were normosmic, and in two of the three families there were no causal variants in other IHH-related genes. Conclusion: We detected three rare sequencing variants in DLG2 in five patients with IHH or delayed puberty in a large IHH cohort. Our results support the contention that the DLG2 mutations are associated with IHH in human puberty.

Genetic Evaluation Supports Differential Diagnosis in Adolescent Patients with Delayed Puberty

Context: Pubertal delay can be the clinical presentation of both idiopathic hypogonadotropic hypogonadism (IHH) and self-limited delayed puberty (SLDP). Distinction between these conditions is a common but important diagnostic challenge in adolescents. Objective: To assess whether gene panel testing can assist with clinical differential diagnosis, to allow accurate and timely management of delayed puberty patients. Design: Retrospective study Methods: Patients presenting with delayed puberty to UK Paediatric services, followed up to final diagnosis, were included. Whole-exome sequencing was analysed using a virtual panel of genes previously reported to cause either IHH or SLDP to identify rare, predicted deleterious variants. Deleterious variants were verified by in silico prediction tools. The correlation between clinical and genotype diagnosis was analysed. Results: Forty-six patients were included, 54% with a final clinical diagnosis of SLDP and 46% with IHH. Red flags signs of IHH were present in only 3 patients. Fifteen predicted deleterious variants in 12 genes were identified in 33% of the cohort, with most inherited in a heterozygous manner. A fair correlation between final clinical diagnosis and genotypic diagnosis was found. Panel testing was able to confirm a diagnosis of IHH in patients with pubertal delay. Genetic analysis identified three patients with IHH that had been previously diagnosed as SLDP. Conclusion:This study supports the use of targeted exome sequencing in the clinical setting to aid the differential diagnosis between IHH and SLDP in adolescents presenting with pubertal delay. Genetic evaluation thus facilitates earlier and more precise diagnosis, allowing clinicians to direct treatment appropriately.

Role of Genetic Analysis for the Differential Diagnosis of Delayed Puberty from the UK Puberty Cohort

Distinction between self-limited delayed puberty (DP) and idiopathic hypogonadotropic hypogonadism (IHH) is challenging. Several biochemical tests have been applied to differentiate these conditions; however, all have limitations resulting in some patients undergoing inappropriate investigations and treatment. This study investigated whether the identification of a genetic defect in patients presenting with pubertal delay in adolescence through whole exome sequencing (WES) can help in distinguishing these two conditions. The WES data of 47 pubertal delay patients from Paediatric Endocrinology and Paediatric services around the UK were analysed. The variants were filtered for rare, predicted deleterious variants in genes from a virtual panel reported in IHH (n= 36), both IHH and self-limited (n=6), and self-limited DP (n= 4) that segregated with trait. Pathogenic variants were verified by Sanger sequencing, computational bioinformatics, and review of inheritance pattern as compared to previous reported mutations in this gene, and assigned a genotypic diagnosis as self-limited DP, IHH or overlapping. Full clinical history, physical examination and basic laboratory and hormonal investigations were used to determine the clinical diagnosis. Clinically, 38% of patients had self-limited DP and 26% had IHH and the rest of uncertain diagnosis as they were still undergoing a period of follow up under the age of 18 years. Twenty-four variants in 17 genes, accounting for 43% of the tested cohort, were identified to be potentially pathogenic variants, with most inherited in a heterozygous manner. We found a good correlation between genotypic diagnosis and phenotype diagnosis with Cohen’s kappa (k) = 0.235 (95% IC, 0.031 to 0.429). Thus, patients who carry variants reported only in self-limited DP with heterozygous inheritance were likely to have a clinical diagnosis of definite self-limited DP. On the other hand, patients carrying homozygous or loss of function variants in genes reported with heterozygous mutations in IHH will be very likely to have IHH. In addition, we identified variants in patients with clinical self-limited DP to have variants, which had been previously reported only in IHH, including DMXL2, CHD7, OTUD4, and SEMA3E. In summary, this study shows that there is a good genotype-phenotype correlation in patients presenting with pubertal delay. Therefore, genetic investigation may help to distinguish these two conditions, resulting in more accurate diagnosis and appropriate treatment modalities. In addition, new genes, previously implicated only in IHH, have been identified in self-limited DP, which indicate that these two conditions share similar disease mechanisms.

Malnutrition in Inflammatory Bowel Diseases. What do we know today?

Growth delay with height and weight impairment is a common feature of pediatric inflammatory bowel diseases (PIBD). Up to 2/3 of Crohn Disease patients have impaired weight at diagnosis, and up to 1/3 have impaired height. Ulcerative colitis usually manifests earlier with less impaired growth, though patients can be affected. Ultimately, growth delay, if not corrected, can reduce final adult height. Weight loss, reduced bone mass, and pubertal delay are also concerns associated with growth delay in newly diagnosed PIBD patients. The mechanisms for growth delay in IBD are multifactorial and include reduced nutrient intake, poor absorption, increased fecal losses, as well as direct effects from inflammation and treatment modalities. Management of growth delay requires optimal disease control. Exclusive enteral nutrition (EEN), biologic therapy, and corticosteroids are the primary induction strategies used in PIBD, and both EEN and biologics positively impact growth and bone development. Beyond adequate disease control, growth delay and pubertal delay require a multidisciplinary approach, dependent on diligent monitoring and identification, nutritional rehabilitation, and involvement of endocrinology and psychiatry services as needed. Pitfalls that clinicians may encounter when managing growth delay include refeeding syndrome, obesity (even in the setting of malnutrition), and restrictive diets. Although treatment of PIBD has improved substantially in the last several decades with the era of biologic therapies and EEN, there is still much to be learned about growth delay in PIBD in order to improve outcomes.

Leydig cell hypoplasia type 1 diagnosed in early childhood with inactivating mutation in LHCGR gene

ABSTRACT Leydig cell aplasia/hypoplasia is an autosomal recessive condition. In its complete form, these patients are 46XY but are cryptorchid and phenotypically female. Most cases reported in literature presented with in adolescence with pubertal delay. We reported a case with a predefined mutation in the LHCGR gene, presenting with swelling in the inguinal region and therefore diagnosed in early childhood. We wanted to emphasize the necessity of keeping Leydig cell hypoplasia in mind in the differential diagnosis of sexual development disorders in early childhood.

Exposure to non-persistent pesticides and puberty timing: a systematic review of the epidemiological evidence

Background: Numerous modern non-persistent pesticides have demonstrated estrogenic/anti-androgenic activity and have been classified as endocrine disrupting chemicals (EDCs). Processes involved in puberty development are vulnerable to EDCs, such as compounds that interfere with the metabolism or activity of sex steroids. Objective: To conduct a systematic review of epidemiological studies on the relationship between early-life exposure to non-persistent pesticides and puberty timing and/or sexual maturation in girls and boys. Methods: A systematic search was carried out using MEDLINE and SCOPUS databases, including original articles published up to November 2020. Results: Thirteen studies were selected after excluding non-original and non-human studies. Exposure to different types of pesticides has been associated with altered puberty timing in girls and/or boys in eight studies. In utero exposure to atrazine has been related to earlier age of menarche in girls; exposure to organophosphate (OP) pesticides has been related to delayed sexual development in boys and girls; childhood pyrethroid exposure has been associated with pubertal delay in girls and pubertal advancement in boys; and prenatal/childhood exposure to multiple pesticides has been linked to earlier puberty onset in girls and pubertal delay in boys. Conclusions: Most of the reviewed studies describe a relationship between pesticide exposure and changes in the age of puberty onset or sex hormone levels, although the quality of the evidence is generally low. Further well-designed longitudinal studies are warranted on specific classes of pesticides and on possible interactions between different types of compounds.

Investigation and Management of Endocrinopathies in Thalassaemia Major

A combination of sub-therapeutic chelation and subsequent iron overload are regarded as the principal drivers of endocrine dysfunction in thalassaemia. The clinical presentation of endocrine complications and their timing of onset can be highly variable, in part due to population heterogeneity but also variation in chelation strategies. Endocrinopathies commonly associated with thalassaemia include: growth delay; pubertal delay; gonadal dysfunction; thyroid disorders; parathyroid and adrenal gland impairment; impaired bone metabolism; and type 2 diabetes mellitus. In this chapter we summarise the main presentations of endocrine disorder in thalassaemia, summarising their epidemiology, clinical presentation and pathophysiologic basis. Furthermore, we review screening, monitoring and treatment strategies, with particular regard to the UK Thalassaemia Society’s 2016 National Standards.