GnRH Deficient Patients With Congenital Hypogonadotropic Hypogonadism: Novel Genetic Findings in ANOS1, RNF216, WDR11, FGFR1, CHD7, and POLR3A Genes in a Case Series and Review of the Literature

Identification of puberty related miRNAs in the hypothalamus of female mice

BACKGROUND AND AIMS

Puberty is a crucial developmental stage marked by the transition from childhood to adulthood, organized by complex hormonal signaling within the neuroendocrine system. The hypothalamus, a central region in this system, regulates pubertal functions through the hypothalamic-pituitary-gonadal (HPG) axis. Gonadotropin-releasing hormone (GnRH) neurons, essential in puberty control, release GnRH in a pulsatile manner, initiating the production of sex hormones. Major influence in pubertal timing has been attributed to genetic predisposition, environmental factors, and nutritional status. MicroRNAs (miRNAs), small non-coding RNA molecules, have emerged as key regulators in various cellular processes by either repressing genes or activating them by inhibiting their repressors. The present study aims to investigate the involvement of miRNAs in the control of puberty.

METHODS

Small RNA sequencing was used to identify and compare the total population of miRNAs in the hypothalamus of female mice before, during and after puberty. Bioinformatic analysis was applied to analyse the expression profile of miRNAs with altered levels followed by pathway enrichment analysis.

RESULTS

Expression levels of several miRNAs were found up- or down-regulated from pre-pubertal to pubertal stage. Furthermore, monitoring the levels of these miRNAs at the post-pubertal stage revealed four expression patterns, in which pathway analysis displayed the associations of these miRNAs with developmental processes, cell cycle regulation, metabolic biosynthesis and epigenetic regulation.

CONCLUSION

The findings of the present study improve our understanding of the molecular pathways underlying puberty and stress the significance of miRNAs in fine-tuning gene expression within the hypothalamus during this critical developmental stage.

Refining antipsychotic treatment strategies in schizophrenia: discovery of genetic biomarkers for enhanced drug response prediction

Schizophrenia (SCZ) is a severe mental disorder affecting around 1% of individuals worldwide. The variability in response to antipsychotic drugs (APDs) among SCZ patients presents a significant challenge for clinicians in determining the most effective medication. In this study, we investigated the biological markers and established a predictive model for APD response based on a large-scale genome-wide association study using 3269 Chinese schizophrenia patients. Each participant underwent an 8-week treatment regimen with one of five mono-APDs: olanzapine, risperidone, aripiprazole, quetiapine, or amisulpride. By dividing the response into ordinal groups of "high", "medium", and "low", we mitigated the bias of unclear treatment outcome and identified three novel significantly associated genetic loci in or near CDH12, WDR11, and ELAVL2. Additionally, we developed predictive models of response to each specific APDs, with accuracies ranging from 79.5% to 98.0%. In sum, we established an effective method to predict schizophrenia patients' response to APDs across three categories, integrating novel biomarkers to guide personalized medicine strategies.

Hypogonadotropic hypogonadism as a cause of NOA and its treatment

ABSTRACT

Hypogonadotropic hypogonadism (HH) represents a relatively rare cause of nonobstructive azoospermia (NOA), but its knowledge is crucial for the clinical andrologists, as it represents a condition that can be corrected with medical therapy in 3 quarters of cases. There are forms of congenital HH, whether or not associated with an absent sense of smell (anosmic HH or Kallmann syndrome, and normosmic HH, respectively), and forms of acquired HH. In congenital HH, complete absence of pubertal development is characteristic. On the other hand, if the deficit occurs after the time of pubertal development, as in acquired HH patients, infertility and typical symptoms of late-onset hypogonadism are the main reasons for seeking medical assistance. Gonadotropin-releasing hormone (GnRH) or gonadotropin replacement therapy is the mainstay of drug therapy and offers excellent results, although a small but significant proportion of patients do not achieve sufficient responses.

Self-administered generational surveys combine with genetic analysis to reveal foundations of depression in Japanese adults

BACKGROUND

Major depressive disorder is a prevalent psychiatric illness characterized by mood disturbances and influenced by various environmental and genetic factors, yet its etiology remains largely unknown.

METHODS

We profiled a self-reported depressive population in Japan with a focus on sociodemographic background, lifestyle, comorbidities, and genetic background, using data from two cohorts, a population-based cohort and a three-generation cohort, recruited by the Tohoku Medical Megabank Organization until December 2021.

RESULTS

Our findings revealed that depression in the Japanese population is strongly associated with certain sociocultural features prevalent in Japan, such as social isolation, neuroticism, and introversion, as well as with well-known risk factors that include age and gender. Environmental factors related to the Great East Japan Earthquake, considered as cohort characteristics, were also strongly associated with the onset of depression. Moreover, using GWAS analysis of whole-genome sequencing data, we identified novel candidate genetic risk variants located on chromosomes 21 and 22 that are associated with depression in Japanese individuals; further validation of these risk variants is warranted.

LIMITATIONS

Our study has limitations, including uncertain clinical relevance resulting from the use of self-reported questionnaires for depression assessment. Additionally, the cohort exhibited a population bias, with greater representation of women than men.

CONCLUSIONS

Our results provide holistic insights into depression risk factors in Japanese adults, although their associations with depression are correlations. This supports the idea that targeted interventions and individualized approaches are important for addressing depression in the Japanese population.

Ring finger protein 216 loss-of-function induces white matter hyperintensities by inhibiting oligodendroglia proliferation

White matter hyperintensities (WMHs) refer to a group of diseases with numerous etiologies while oligodendrocytes remain the centerpiece in the pathogenesis of WMHs. Ring Finger Protein 216 (RNF216) encodes a ubiquitin ligase, and its mutation begets WMHs, ataxia, and cognitive decline in patients. Yet no study has revealed the function of RNF216 in oligodendroglia and WHIs before. In this study, we summarized the phenotypes of RNF216-mutation cases and explored the normal distribution of RNF216 in distinct brain regions and neuronal cells by bioinformatic analysis. Furthermore, MO3.13, a human oligodendrocyte cell line, was applied to study the function alteration after RNF216 knockdown. As a result, WMHs were the most common symptom in RNF216-mutated diseases, and RNF216 was indeed relatively enriched in corpus callosum and oligodendroglia in humans. The downregulation of RNF216 in oligodendroglia remarkably hampered cell proliferation by inhibiting the Akt pathway while having no significant effect on cell injury and oligodendrocyte maturation. Combining clinical, bioinformatical, and experimental evidence, our study implied the pivotal role of RNF216 in WMHs which might serve as a potent target in the therapy of WMHs.

Clinical and genetic spectrum of RNF216-related disorder: a new case and literature review

BACKGROUND

Cases of RNF216-related disorder have been reported sporadically. However, the clinical and genetic spectrum of this disorder has not been fully studied.

METHODS

We identified an individual with a novel causative RNF216 variant in our institution and reviewed all individuals with causative RNF216 variants in previous reports. The clinical and genetic features of all the described individuals were analysed and summarised.

RESULTS

Twenty-four individuals from 17 families with causative RNF216 variants were identified. The mean age at the onset of neurological symptoms was 29.2 years (range 18-49 years). Ataxia (57%) was the most frequent initial symptoms in individuals under 30 years old, while chorea (63%) was the most frequent initial symptom in individuals over 30 years old. Over 90% of individuals presented with cognitive impairment and hypogonadotropic hypogonadism throughout the disease. White matter lesions (96%) and cerebellar atrophy (92%) were the most common imaging findings. Twenty pathogenic variants in RNF216 were detected. The variants in 12 (71%) families were inherited in a monogenic recessive pattern, whereas the variants in 5 (29%) were inherited in a digenic pattern by acting with variants in other genes. The majority of the RNF216 variants (85%) resulted in amino acid changes or the truncation of the 'RING between RING' (RBR) domain or C-terminal extension.

CONCLUSION

RNF216-related disorder is an inherited neuroendocrine disease characterised by cerebellar ataxia, chorea, cognitive impairment and hypogonadotropic hypogonadism. Most causative variants in patients with RNF216-related disorder influence the RBR domain or C-terminal extension of RNF216.

Genetic diagnosis of endocrine disorders in Cyprus through the Cyprus Institute of Neurology and Genetics: an ENDO-ERN Reference Center

The report covers the current and past activities of the department Molecular Genetics-Function and Therapy (MGFT) at the Cyprus Institute of Neurology and Genetics (CING), an affiliated Reference Center for the European Reference Network on Rare Endocrine Conditions (Endo-ERN).The presented data is the outcome of > 15 years long standing collaboration between MGFT and endocrine specialists from the local government hospitals and the private sector. Up-to-date > 2000 genetic tests have been performed for the diagnosis of inherited rare endocrine disorders. The major clinical entities included Congenital Adrenal Hyperplasia (CAH) due to pathogenic variants in CYP21A2 gene and Multiple Endocrine Neoplasia (MEN) type 2 due to pathogenic variants in the RET proto-oncogene. Other rare and novel pathogenic variants in ANOS1, WDR11, FGFR1, RNF216, and CHD7 genes were also found in patients with Congenital Hypogonadotropic Hypogonadism. Interestingly, a few patients with Disorders of Sexual Differentiation (DSD) shared rare pathogenic variants in the SRD5A2, HSD17B3 and HSD3B2 while patients with Glucose and Insulin Homeostasis carried theirs in GCK and HNF1A genes. Lastly, MGFT over the last few years has established an esteemed diagnostic and research program on premature puberty with emphasis on the implication of MKRN3 gene on the onset of the disease and the identification of other prognosis biomarkers.As an Endo-ERN member MGFT department belongs to this large European network and holds the same humanistic ideals which aim toward the improvements of health care for patients with rare endocrine conditions in respect to improved and faster diagnosis.

Digenic CHD7 and SMCHD1 inheritance Unveils phenotypic variability in a family mainly presenting with hypogonadotropic hypogonadism

Objectives

CHARGE syndrome is a congenital hereditary condition involving multiple systems. Patients are easily misdiagnosed with idiopathic hypogonadotropic hypogonadism (IHH) due to the overlap of clinical manifestations. An accurate clinical diagnosis remains challenging when the predominant clinical manifestation resembles hypogonadotropic hypogonadism.

Methods

This original research is conducted based on the genetic finding and analysis of clinical cases. Whole-exome sequencing (WES) and in-silico analyse were performed on two sisters to investigate the pathogenesis in this family. Homology modelling was conducted to evaluate structural changes in the variants.

Results

WES and Sanger sequencing revealed two siblings carrying a nonsense mutation (NM_017780.4: c.115C > T) in exon 2 of CHD7 inherited from a mildly affected mother and a missense mutation (NM_015295.3: c.2582T > C) in exon 20 of SMCHD1 inherited from an asymptomatic father. The nonsense mutation in CHD7 was predicted to generate nonsense-mediated decay, whereas the missense mutation in SMCHD1 decreased protein stability.

Conclusions

We identified digenic CHD7 and SMCHD1 mutations in IHH-associated diseases for the first time and verified the synergistic role of oligogenic inheritance. It was also determined that WES is an effective tool for distinguishing diseases with overlapping features and establishing a molecular diagnosis for cases with digenic or oligogenic hereditary disorders, which is beneficial for timely treatment, and family genetic counseling.

Gonadotropin-Releasing Hormone Receptor (GnRHR) and Hypogonadotropic Hypogonadism

Human sexual and reproductive development is regulated by the hypothalamic-pituitary-gonadal (HPG) axis, which is primarily controlled by the gonadotropin-releasing hormone (GnRH) acting on its receptor (GnRHR). Dysregulation of the axis leads to conditions such as congenital hypogonadotropic hypogonadism (CHH) and delayed puberty. The pathophysiology of GnRHR makes it a potential target for treatments in several reproductive diseases and in congenital adrenal hyperplasia. GnRHR belongs to the G protein-coupled receptor family and its GnRH ligand, when bound, activates several complex and tissue-specific signaling pathways. In the pituitary gonadotrope cells, it triggers the G protein subunit dissociation and initiates a cascade of events that lead to the production and secretion of the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) accompanied with the phospholipase C, inositol phosphate production, and protein kinase C activation. Pharmacologically, GnRHR can be modulated by synthetic analogues. Such analogues include the agonists, antagonists, and the pharmacoperones. The agonists stimulate the gonadotropin release and lead to receptor desensitization with prolonged use while the antagonists directly block the GnRHR and rapidly reduce the sex hormone production. Pharmacoperones include the most recent GnRHR therapeutic approaches that directly correct the misfolded GnRHRs, which are caused by genetic mutations and hold serious promise for CHH treatment. Understanding of the GnRHR's genomic and protein structure is crucial for the most appropriate assessing of the mutation impact. Such mutations in the GNRHR are linked to normosmic hypogonadotropic hypogonadism and lead to various clinical symptoms, including delayed puberty, infertility, and impaired sexual development. These mutations vary regarding their mode of inheritance and can be found in the homozygous, compound heterozygous, or in the digenic state. GnRHR expression extends beyond the pituitary gland, and is found in reproductive tissues such as ovaries, uterus, and prostate and non-reproductive tissues such as heart, muscles, liver and melanoma cells. This comprehensive review explores GnRHR's multifaceted role in human reproduction and its clinical implications for reproductive disorders.

A novel mutation in RNF216 gene in a Turkish case with Gordon Holmes syndrome

BACKGROUND

Gordon Holmes syndrome (GHS) is a rare autosomal recessive disorder characterized by hypogonadotropic hypogonadism, cognitive decline, and cerebellar ataxia. Mutations in the Ring Finger Protein 216 (RNF216) gene have been known to be associated with GHS therewithal RNF216 mutations have been detected in cases with Huntington-like disease, 4H syndrome (hypodontia, hypomyelination, ataxia and hypogonadotropic hypogonadism), and congenital hypogonadotropic hypogonadism.

CASE PRESENTATION

Here we report a novel homozygous frameshift mutation in RNF216 gene c.1860_1861dupCT (p.Cys621SerfsTer56) in a patient with hypogonadotropic hypogonadism, ataxia, and cognitive decline diagnosed with GHS also co-occurrence of parkinsonism and dystonia which was not reported before.

CONCLUSIONS

We report an extremely rare case of GHS. The core features of GHS are well defined, but genotype-phenotype correlations are still limited. To understand the pathophysiology of different phenotypes, the type and localization of novel mutations need to be defined, and the effect of these different variants on clinical features needs to be determined. Further studies should explain the factors of phenotypic variability present in GHS patients with RNF216 mutations.

Genetic Analysis of Patients with Congenital Hypogonadotropic Hypogonadism: A Case Series

Congenital hypogonadotropic hypogonadism (cHH)/Kallmann syndrome (KS) is a rare genetic disorder with variable penetrance and a complex inheritance pattern. Consequently, it does not always follow Mendelian laws. More recently, digenic and oligogenic transmission has been recognized in 1.5-15% of cases. We report the results of a clinical and genetic investigation of five unrelated patients with cHH/KS analyzed using a customized gene panel. Patients were diagnosed according to the clinical, hormonal, and radiological criteria of the European Consensus Statement. DNA was analyzed using next-generation sequencing with a customized panel that included 31 genes. When available, first-degree relatives of the probands were also analyzed to assess genotype-phenotype segregation. The consequences of the identified variants on gene function were evaluated by analyzing the conservation of amino acids across species and by using molecular modeling. We found one new pathogenic variant of the CHD7 gene (c.576T>A, p.Tyr1928) and three new variants of unknown significance (VUSs) in IL17RD (c.960G>A, p.Met320Ile), FGF17 (c.208G>A, p.Gly70Arg), and DUSP6 (c.434T>G, p.Leu145Arg). All were present in the heterozygous state. Previously reported heterozygous variants were also found in the PROK2 (c.163del, p.Ile55*), CHD7 (c.c.2750C>T, p.Thr917Met and c.7891C>T, p.Arg2631*), FLRT3 (c.1106C>T, p.Ala369Val), and CCDC103 (c.461A>C, p.His154Pro) genes. Molecular modeling, molecular dynamics, and conservation analyses were performed on three out of the nine variants identified in our patients, namely, FGF17 (p.Gly70Arg), DUSP6 (p.Leu145Arg), and CHD7 p.(Thr917Met). Except for DUSP6, where the L145R variant was shown to disrupt the interaction between β6 and β3, needed for extracellular signal-regulated kinase 2 (ERK2) binding and recognition, no significant changes were identified between the wild-types and mutants of the other proteins. We found a new pathogenic variant of the CHD7 gene. The molecular modeling results suggest that the VUS of the DUSP6 (c.434T>G, p.Leu145Arg) gene may play a role in the pathogenesis of cHH. However, our analysis indicates that it is unlikely that the VUSs for the IL17RD (c.960G>A, p.Met320Ile) and FGF17 (c.208G>A, p.Gly70Arg) genes are involved in the pathogenesis of cHH. Functional studies are needed to confirm this hypothesis.

Panel testing for the molecular genetic diagnosis of congenital hypogonadotropic hypogonadism – a clinical perspective

Congenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder that results in reproductive hormone deficiency and reduced potential for fertility in adult life. Discoveries of the genetic aetiology of CHH have advanced dramatically in the past 30 years, with currently over 40 genes recognised to cause or contribute to the development of this condition. The genetic complexity of CHH is further increased by the observation of di- and oligogenic, as well as classic monogenic, inheritance and incomplete penetrance. Very recently in the UK, a panel of 14 genes has been curated for the genetic diagnosis of CHH within the NHS Genomic Medicine Service programme. The aim of this review is to appraise the advantages and potential pitfalls of the use of a CHH panel in clinical endocrine diagnostics, and to consider the future avenues for developing this panel including the potential of whole exome or whole genome sequencing data analysis in this condition.

Adult-onset reversible idiopathic hypogonadotropic hypogonadism in male adult carrying a WDR11 missense mutation

Idiopathic hypogonadotropic hypogonadism (IHH) occurs mostly in childhood or adolescence and very rarely in adulthood. It is characterised by delayed onset of secondary sexual characteristics. Many genetic abnormalities have been reported in congenital IHH cases, but rarely in adult-onset IHH cases. IHH requires lifelong hormone replacement therapy; however, a few reports suggest the reversibility of this condition.

In this case, after having his first child, a man in his 20s was diagnosed with gynecomastia followed by IHH. He improved with gonadotropin-releasing hormone replacement therapy and had two more children. The treatment was discontinued after 4 years, but the improvement was sustained. He had a heterozygous missense variant in WDR11 (c.2390G>A; p.Arg797His), which may play a role in adult-onset IHH reversal. Accumulation of such cases can contribute to our understanding of the pathogenesis and genetic component of IHH.

Novel Genomic Variants, Atypical Phenotypes and Evidence of a Digenic/Oligogenic Contribution to Disorders/Differences of Sex Development in a Large North African Cohort

In a majority of individuals with disorders/differences of sex development (DSD) a genetic etiology is often elusive. However, new genes causing DSD are routinely reported and using the unbiased genomic approaches, such as whole exome sequencing (WES) should result in an increased diagnostic yield. Here, we performed WES on a large cohort of 125 individuals all of Algerian origin, who presented with a wide range of DSD phenotypes. The study excluded individuals with congenital adrenal hypoplasia (CAH) or chromosomal DSD. Parental consanguinity was reported in 36% of individuals. The genetic etiology was established in 49.6% (62/125) individuals of the total cohort, which includes 42.2% (35/83) of 46, XY non-syndromic DSD and 69.2% (27/39) of 46, XY syndromic DSD. No pathogenic variants were identified in the 46, XX DSD cases (0/3). Variants in the AR, HSD17B3, NR5A1 and SRD5A2 genes were the most common causes of DSD. Other variants were identified in genes associated with congenital hypogonadotropic hypogonadism (CHH), including the CHD7 and PROKR2. Previously unreported pathogenic/likely pathogenic variants (n = 30) involving 25 different genes were identified in 22.4% of the cohort. Remarkably 11.5% of the 46, XY DSD group carried variants classified as pathogenic/likely pathogenic variant in more than one gene known to cause DSD. The data indicates that variants in PLXNA3, a candidate CHH gene, is unlikely to be involved in CHH. The data also suggest that NR2F2 variants may cause 46, XY DSD.

Whole Exome Sequencing Points towards a Multi-Gene Synergistic Action in the Pathogenesis of Congenital Combined Pituitary Hormone Deficiency

Combined pituitary hormone deficiency (CPHD) is characterized by deficiency of growth hormone and at least one other pituitary hormone. Pathogenic variants in more than 30 genes expressed during the development of the head, hypothalamus, and/or pituitary have been identified so far to cause genetic forms of CPHD. However, the etiology of around 85% of the cases remains unknown. The aim of this study was to unveil the genetic etiology of CPHD due to congenital hypopituitarism employing whole exome sequencing (WES) in two newborn patients, initially tested and found to be negative for PROP1, LHX3, LHX4 and HESX1 pathogenic variants by Sanger sequencing and for copy number variations by MLPA. In this study, the application of WES in these CPHD newborns revealed the presence of three different heterozygous gene variants in each patient. Specifically in patient 1, the variants BMP4; p.Ala42Pro, GNRH1; p.Arg73Ter and SRA1; p.Gln32Glu, and in patient 2, the SOX9; p.Val95Ile, HS6ST1; p.Arg306Gln, and IL17RD; p.Pro566Ser were identified as candidate gene variants. These findings further support the hypothesis that CPHD constitutes an oligogenic rather than a monogenic disease and that there is a genetic overlap between CPHD and congenital hypogonadotropic hypogonadism.

Differential expression profiles of microRNAs in musk gland of unmated and mated forest musk deer (Moschus berezovskii)

Background

The formation of musk is a complex biophysical and biochemical process that change with the rut of male forest musk deer. We have reported that the mating status of male forest musk deer might result to the variations of chemical composition and microbiota of musk and its yields. Critical roles for microRNAs (miRNAs) of multi-tissues were profiled in our previous study; however, the role for miRNAs of the musk gland remains unclear in this species.

Methods

In this study, we used Illumina deep sequencing technology to sequence the small RNA transcriptome of unmated male (UM) and mated male (UM) of Chinese forest musk deer.

Results

We identified 1,652 known miRNAs and 45 novel miRNAs, of which there were 174 differentially expressed miRNAs between UM and MM. chi-miR-21-5p, ipu-miR-99b and bta-miR-26a were up-regulated in UM among the 10 most differentially expressed miRNAs. Functional enrichment of the target genes showed that monosaccharide biosynthetic process, protein targeting, cellular protein catabolic process enriched higher in MM. Meanwhile, structural molecule activity, secretion by cell, regulated exocytosis and circulatory system process enriched more in UM, hinting that the formation of musk in UM was mediated by target genes related to exocytosis. The miRNA-mRNA pairs such as miR-21: CHD7, miR143: HSD17B7, miR-141/200a: Noc2 might involve in musk gland development and musk secretion, which need to be verified in future study.

Congenital hypogonadotropic hypogonadism: from clinical characteristics to genetic aspects

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder caused by a deficiency in gonadotropin-releasing hormone (GnRH). CHH is characterized by delayed puberty and/or infertility; this is because GnRH is the main component of the hypothalamic-pituitary-gonadal (HPG) axis, which is a key factor in pubertal development and reproductive function completion. However, since the development of sexual characteristics and reproduction begins in the prenatal period and is very complex and delicate, the clinical characteristics and involved genes are very diverse. In particular, the HPG axis is activated three times in a lifetime, and the symptoms and biochemical findings of CHH vary by period. In addition, related genes also vary according to the formation and activation process of the HPG axis. In this review, the clinical characteristics and treatment of CHH according to HPG axis activation and different developmental periods are reviewed, and the related genes are summarized according to their pathological mechanisms.

Pathogenic and Low-Frequency Variants in Children With Central Precocious Puberty

Background

Central precocious puberty (CPP) due to premature activation of GnRH secretion results in early epiphyseal fusion and to a significant compromise in the achieved final adult height. Currently, few genetic determinants of children with CPP have been described. In this translational study, rare sequence variants in MKRN3, DLK1, KISS1, and KISS1R genes were investigated in patients with CPP.

Methods

Fifty-four index girls and two index boys with CPP were first tested by Sanger sequencing for the MKRN3 gene. All children found negative (n = 44) for the MKRN3 gene were further investigated by whole exome sequencing (WES). In the latter analysis, the status of variants in genes known to be related with pubertal timing was compared with an in-house Cypriot control cohort (n = 43). The identified rare variants were initially examined by in silico computational algorithms and confirmed by Sanger sequencing. Additionally, a genetic network for the MKRN3 gene, mimicking a holistic regulatory depiction of the crosstalk between MKRN3 and other genes was designed.

Results

Three previously described pathogenic MKRN3 variants located in the coding region of the gene were identified in 12 index girls with CPP. The most prevalent pathogenic MKRN3 variant p.Gly312Asp was exclusively found among the Cypriot CPP cohort, indicating a founder effect phenomenon. Seven other CPP girls harbored rare likely pathogenic upstream variants in the MKRN3. Among the 44 CPP patients submitted to WES, nine rare DLK1 variants were identified in 11 girls, two rare KISS1 variants in six girls, and two rare MAGEL2 variants in five girls. Interestingly, the frequent variant rs10407968 (p.Gly8Ter) of the KISS1R gene appeared to be less frequent in the cohort of patients with CPP.

Conclusion

The results of the present study confirm the importance of the MKRN3-imprinted gene in genetics of CPP and its key role in pubertal timing. Overall, the results of the present study have emphasized the importance of an approach that aligns genetics and clinical aspects, which is necessary for the management and treatment of CPP.

Complex Modes of Inheritance in Hereditary Red Blood Cell Disorders: A Case Series Study of 155 Patients

Hereditary erythrocytes disorders include a large group of conditions with heterogeneous molecular bases and phenotypes. We analyzed here a case series of 155 consecutive patients with clinical suspicion of hereditary erythrocyte defects referred to the Medical Genetics Unit from 2018 to 2020. All of the cases followed a diagnostic workflow based on a targeted next-generation sequencing panel of 86 genes causative of hereditary red blood cell defects. We obtained an overall diagnostic yield of 84% of the tested patients. Monogenic inheritance was seen for 69% (107/155), and multi-locus inheritance for 15% (23/155). PIEZO1 and SPTA1 were the most mutated loci. Accordingly, 16/23 patients with multi-locus inheritance showed dual molecular diagnosis of dehydrated hereditary stomatocytosis/xerocytosis and hereditary spherocytosis. These dual inheritance cases were fully characterized and were clinically indistinguishable from patients with hereditary spherocytosis. Additionally, their ektacytometry curves highlighted alterations of dual inheritance patients compared to both dehydrated hereditary stomatocytosis and hereditary spherocytosis. Our findings expand the genotypic spectrum of red blood cell disorders and indicate that multi-locus inheritance should be considered for analysis and counseling of these patients. Of note, the genetic testing was crucial for diagnosis of patients with a complex mode of inheritance.

Neurobiology of puberty and its disorders

Puberty, which in humans is considered to include both gonadarche and adrenarche, is the period of becoming capable of reproducing sexually and is recognized by maturation of the gonads and development of secondary sex characteristics. Gonadarche referring to growth and maturation of the gonads is fundamental to puberty since it encompasses increased gonadal steroid secretion and initiation of gametogenesis resulting from enhanced pituitary gonadotropin secretion, triggered in turn by robust pulsatile GnRH release from the hypothalamus. This chapter reviews the development of GnRH pulsatility from before birth until the onset of puberty. In humans, GnRH pulse generation is restrained during childhood and juvenile development. This prepubertal hiatus in hypothalamic activity is considered to result from a neurobiological brake imposed upon the GnRH pulse generator resident in the infundibular nucleus. Reactivation of the GnRH pulse generator initiates pubertal development. Current understanding of the genetics and physiology of the brake will be discussed, as will hypotheses proposed to account for timing the resurgence in pulsatile GnRH and initiation of puberty. The chapter ends with a discussion of disorders associated with precocious or delayed puberty with a focus on those with etiologies attributed to aberrant GnRH neuron anatomy or function. A pediatric approach to patients with pubertal disorders is provided and contemporary treatments for both precocious and delayed puberty outlined.