scholarly journals Oligogenic Inheritance Underlying Incomplete Penetrance of PROKR2 Mutations in Hypogonadotropic Hypogonadism

2021 ◽  
Vol 12 ◽  
Author(s):  
Rahma Mkaouar ◽  
Lamia Cherif Ben Abdallah ◽  
Chokri Naouali ◽  
Saida Lahbib ◽  
Zinet Turki ◽  
...  
Keyword(s):  
Hypogonadotropic Hypogonadism ◽  
Hormone Secretion ◽  
Autosomal Recessive Inheritance ◽  
Human Reproduction ◽  
Incomplete Penetrance ◽  
Loss Of Function ◽  
Prokineticin 2 ◽  
Tunisian Patients ◽  
Genetic Mechanisms ◽  
Oligogenic Inheritance

The role of the prokineticin 2 pathway in human reproduction, olfactory bulb morphogenesis, and gonadotropin-releasing hormone secretion is well established. Recent studies have highlighted the implication of di/oligogenic inheritance in this disorder. In the present study, we aimed to identify the genetic mechanisms that could explain incomplete penetrance in hypogonadotropic hypogonadism (HH). This study involved two unrelated Tunisian patients with HH, which was triggered by identifying a homozygous p.(Pro290Ser) mutation in the PROKR2 gene in a girl (HH1) with Kallmann syndrome (KS). The functional effect of this variant has previously been well demonstrated. Unexpectedly, her unaffected father (HH1P) and brother (HH1F) also carried this genetic variation at a homozygous state. In the second family, we identified a heterozygous p.(Lys205del) mutation in PROKR2, both in a male patient with normosmic idiopathic IHH (HH12) and his asymptomatic mother. Whole-exome sequencing in the three HH1 family members allowed the identification of additional variants in the prioritized genes. We then carried out digenic combination predictions using the oligogenic resource for variant analysis (ORVAL) software. For HH1, we found the highest number of disease-causing variant pairs. Notably, a CCDC141 variant (c.2803C > T) was involved in 18 pathogenic digenic combinations. The CCDC141 variant acts in an autosomal recessive inheritance mode, based on the digenic effect prediction data. For the second patient (HH12), prediction by ORVAL allowed the identification of an interesting pathogenic digenic combination between DUSP6 and SEMA7A genes, predicted as “dual molecular diagnosis.” The SEMA7A variant p.(Glu436Lys) is novel and predicted as a VUS by Varsome. Sanger validation revealed the absence of this variant in the healthy mother. We hypothesize that disease expression in HH12 could be induced by the digenic transmission of the SEMA7A and DUSP6 variants or a monogenic inheritance involving only the SEMA7A VUS if further functional assays allow its reclassification into pathogenic. Our findings confirm that homozygous loss-of-function genetic variations are insufficient to cause KS, and that oligogenism is most likely the main transmission mode involved in Congenital Hypogonadotropic Hypogonadism.

scholarly journals Loss-of-Function Mutations in the Genes Encoding Prokineticin-2 or Prokineticin Receptor-2 Cause Autosomal Recessive Kallmann Syndrome

2008 ◽  
Vol 93 (10) ◽  
pp. 4113-4118 ◽  
Author(s):  
Ana Paula Abreu ◽  
Ericka Barbosa Trarbach ◽  
Margaret de Castro ◽  
Elaine Maria Frade Costa ◽  
Beatriz Versiani ◽  
...  
Keyword(s):  
Hypogonadotropic Hypogonadism ◽  
Critical Role ◽  
Kallmann Syndrome ◽  
Control Group ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Coding Regions ◽  
Prokineticin 2 ◽  
Bilateral Cryptorchidism ◽  
Genes Encoding

Context: Physiological activation of the prokineticin pathway has a critical role in olfactory bulb morphogenesis and GnRH secretion in mice. Objective: To investigate PROK2 and PROKR2 mutations in patients with hypogonadotropic hypogonadism (HH) associated or not with olfactory abnormalities. Design: We studied 107 Brazilian patients with HH (63 with Kallmann syndrome and 44 with normosmic HH) and 100 control individuals. The coding regions of PROK2 and PROKR2 were amplified by PCR followed by direct automatic sequencing. Results: In PROK2, two known frameshift mutations were identified. Two brothers with Kallmann syndrome harbored the homozygous p.G100fsX121 mutation, whereas one male with normosmic HH harbored the heterozygous p.I55fsX56 mutation. In PROKR2, four distinct mutations (p.R80C, p.Y140X, p.L173R, and p.R268C) were identified in five patients with Kallmann syndrome and in one patient with normosmic HH. These mutations were not found in the control group. The p.R80C, p.L173R, and p.R268C missense mutations were identified in the heterozygous state in the HH patients and in their asymptomatic first-degree relatives. In addition, no mutations of FGFR1, KAL1, GnRHR, KiSS-1, or GPR54 were identified in these patients. Notably, the new nonsense mutation (p.Y140X) was identified in the homozygous state in an anosmic boy with micropenis, bilateral cryptorchidism, and high-arched palate. His asymptomatic parents were heterozygous for this severe defect. Conclusion: We expanded the repertoire of PROK2 and PROKR2 mutations in patients with HH. In addition, we show that PROKR2 haploinsufficiency is not sufficient to cause Kallmann syndrome or normosmic HH, whereas homozygous loss-of-function mutations either in PROKR2 or PROK2 are sufficient to cause disease phenotype, in accordance with the Prokr2 and Prok2 knockout mouse models.

scholarly journals Kisspeptin and the Hypothalamic Control of Reproduction: Lessons from the Human

Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5130-5136 ◽  
Author(s):  
Jyothis T. George ◽  
Stephanie B. Seminara
Keyword(s):  
G Protein ◽  
Mammalian Species ◽  
Hypogonadotropic Hypogonadism ◽  
Experimental Studies ◽  
Clinical Syndrome ◽  
Human Reproduction ◽  
Loss Of Function ◽  
G Protein Coupled Receptor ◽  
Gonadotropin Secretion ◽  
G Protein Coupled

Abstract The hypothalamic hormone GnRH is a central driver of pituitary gonadotropin secretion, controlling pulsatile gonadotropin secretion, modulating gonadal steroid feedback, and bringing about full fertility in the adult. Thus, understanding GnRH neuronal regulation is essential to understanding the neurohumoral control of human reproduction. Genetic tools were used in patients with GnRH deficiency (i.e. idiopathic hypogonadotropic hypogonadism), a clinical syndrome that results from the failure of a normal pattern of pulsatile GnRH, to discover upstream modulators of GnRH secretion (1). In 2003, homozygosity mapping of two consanguineous pedigrees led to the identification of loss of function mutations in KISS1R (a G protein coupled receptor) by two groups (2, 3). In parallel, the Kiss1r−/− mouse was shown to be a phenocopy of the human GnRH-deficient state, demonstrating that the function of KISS1R/Kiss1r is conserved across mammalian species (4). Just before these human genetic discoveries, the ligand for kisspeptin-1 receptor [KISS1R; also known as G protein coupled receptor 54 (GPR54)], was discovered to be kisspeptin. Soon thereafter a large array of experimental studies began assembling genetic, expression, physiologic, transgenic, knockdown, and electrophysiological data to characterize the physiology of kisspeptin and its seminal role in modulating GnRH release.

scholarly journals New insights in the genetics of isolated hypogonadotropic hypogonadism

2004 ◽  
pp. U83-U88 ◽  
Author(s):  
A Iovane ◽  
C Aumas ◽  
N de Roux
Keyword(s):  
Fibroblast Growth Factor Receptor ◽  
Hypogonadotropic Hypogonadism ◽  
Hormone Secretion ◽  
Growth Factor Receptor ◽  
Kallmann Syndrome ◽  
Loss Of Function ◽  
Genetic Studies ◽  
Familial Cases ◽  
Gonadotropic Axis ◽  
Inactivating Mutations

Isolated gonadotropic deficiency or isolated hypogonadotropic hypogonadism is defined as a low sexual hormone secretion by the gonads associated with low LH and FSH plasma levels. Kallmann syndrome is defined as a congenital isolated gonadotropic deficiency associated with anosmia whereas the phenotype of the idiopathic form is limited to the gonadotropic axis. For several years, it has been known that mutations of the KAL-1 gene or loss-of-function mutations of GnRH receptor did not explain all familial cases of isolated gonadotropic deficiency with or without anosmia. Thus the existence of other genes playing a major role in the physiology of the gonadotropic axis was highly suggested. In 2003, fibroblast growth factor receptor 1 (FGFR1) and GPR54 were shown to be two of these genes. FGFR1 loss-of-function mutations were reported in Kallmann syndrome whereas inactivating mutations of GPR54 were described in the idiopathic form of the gonadotropic deficiency. These genetic studies have opened up a new chapter in the physiology and the pharmacology of the gonadotropic axis.

Cryptozoospermia after treatment with clomiphene citrate following long-term use of intramuscular testosterone undecanoate depot injection (Nebido®)

2019 ◽  
Vol 39 (2) ◽  
Author(s):  
Tanja Grubić Kezele
Keyword(s):  
Clomiphene Citrate ◽  
Hypogonadotropic Hypogonadism ◽  
Human Reproduction ◽  
Testosterone Replacement Therapy ◽  
Testosterone Undecanoate ◽  
Clinical Hospital ◽  
Receptor Modulator ◽  
Depot Injection ◽  
Gonadal Failure ◽  
Hospital Center

Abstract Objective To illustrate the importance of treatment duration with intramuscular testosterone undecanoate (Nebido®) for the final spermatogenesis recovery after treatment cessation. Also, to show a subsequent poor efficacy of the selective estrogen receptor modulator (SERM) clomiphene citrate (CC) in treating steroid-induced azoospermia following Nebido® cessation and describe that initial oligozoospermia, existing before starting Nebido®, largely contributes to that treatment outcome. Methodology Setting: Department of Human Reproduction and Department of Endocrinology, Clinical Hospital Center Rijeka, Rijeka, and Department of Endocrinology, Clinical Hospital Center Sestre milosrdnice, Zagreb, Croatia. Patient: A male patient having been diagnosed with primary hypogonadotropic hypogonadism, oligozoospermia and low testosterone (T) level, was treated with intramuscular testosterone undecanoate (TU) depot 1 g (Nebido®) to prevent further progression of testosterone deficiency symptoms (low mood, energy and concentration, fatigue, muscle weakness). Interventions: Stopping Nebido® and treatment with CC 50 mg per day 5 days per week for 3–6 month to recover spermatogenesis. Main outcome measures: T levels and semen analyses. Results Semen analyses did not return to values before taking Nebido® 1 year after cessation nor after 3 months of treatment with CC. Values of T, follicle stimulating hormone (FSH) and luteinizing hormone (LH) dropped even more than before starting Nebido®, after 1 year of cessation. Conclusions Here we describe a case of initially idiopathic gonadal failure with subsequent secondary gonadal failure and infertility resulting from testosterone replacement therapy (TRT) treatment, and poor spermatogenesis recovery outcome of CC used post Nebido® cessation.

scholarly journals A family harboring an MLKL loss of function variant implicates impaired necroptosis in diabetes

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Joanne M. Hildebrand ◽  
Bernice Lo ◽  
Sara Tomei ◽  
Valentina Mattei ◽  
Samuel N. Young ◽  
...  
Keyword(s):  
Potential Role ◽  
Autosomal Dominant ◽  
Inflammatory Diseases ◽  
Diabetic Patients ◽  
Incomplete Penetrance ◽  
Loss Of Function ◽  
Healthy Sibling ◽  
Dominant Disease ◽  
Terminal Effector

AbstractMaturity-onset diabetes of the young, MODY, is an autosomal dominant disease with incomplete penetrance. In a family with multiple generations of diabetes and several early onset diabetic siblings, we found the previously reported P33T PDX1 damaging mutation. Interestingly, this substitution was also present in a healthy sibling. In contrast, a second very rare heterozygous damaging mutation in the necroptosis terminal effector, MLKL, was found exclusively in the diabetic family members. Aberrant cell death by necroptosis is a cause of inflammatory diseases and has been widely implicated in human pathologies, but has not yet been attributed functions in diabetes. Here, we report that the MLKL substitution observed in diabetic patients, G316D, results in diminished phosphorylation by its upstream activator, the RIPK3 kinase, and no capacity to reconstitute necroptosis in two distinct MLKL−/− human cell lines. This MLKL mutation may act as a modifier to the P33T PDX1 mutation, and points to a potential role of impairment of necroptosis in diabetes. Our findings highlight the importance of family studies in unraveling MODY’s incomplete penetrance, and provide further support for the involvement of dysregulated necroptosis in human disease.

The LARGE2-APO1/APO2 regulatory module controls panicle size and grain number in rice

2021 ◽  
Author(s):  
Luojiang Huang ◽  
Kai Hua ◽  
Ran Xu ◽  
Dali Zeng ◽  
Ruci Wang ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Loss Of Function ◽  
Grain Number ◽  
Hect Domain ◽  
Regulatory Module ◽  
Promising Target ◽  
Meristematic Activity ◽  
Positive Regulators ◽  
Genetic Mechanisms ◽  
Biochemical Analyses

Abstract Panicle size and grain number are important agronomic traits and influence grain yield in rice (Oryza sativa), but the molecular and genetic mechanisms underlying panicle size and grain number control remain largely unknown in crops. Here we report that LARGE2 encodes a HECT-domain E3 ubiquitin ligase OsUPL2 and regulates panicle size and grain number in rice. The loss of function large2 mutants produce large panicles with increased grain number, wide grains and leaves, and thick culms. LARGE2 regulates panicle size and grain number by repressing meristematic activity. LARGE2 is highly expressed in young panicles and grains. Biochemical analyses show that LARGE2 physically associates with ABERRANT PANICLE ORGANIZATION1 (APO1) and APO2, two positive regulators of panicle size and grain number, and modulates their stabilities. Genetic analyses support that LARGE2 functions with APO1 and APO2 in a common pathway to regulate panicle size and grain number. These findings reveal a novel genetic and molecular mechanism of the LARGE2-APO1/APO2 module-mediated control of panicle size and grain number in rice, suggesting that this module is a promising target for improving panicle size and grain number in crops.

Genetic control of dorsal-ventral identity in the telencephalon: opposing roles for Pax6 and Gsh2

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4361-4371 ◽  
Author(s):  
H. Toresson ◽  
S.S. Potter ◽  
K. Campbell
Keyword(s):  
Cerebral Cortex ◽  
Gene Function ◽  
Abnormal Development ◽  
Loss Of Function ◽  
Embryonic Mouse ◽  
Molecular Identity ◽  
Mouse Mutants ◽  
Germinal Zone ◽  
Genetic Mechanisms ◽  
Dlx Genes

We have examined the genetic mechanisms that regulate dorsal-ventral identity in the embryonic mouse telencephalon and, in particular, the specification of progenitors in the cerebral cortex and striatum. The respective roles of Pax6 and Gsh2 in cortical and striatal development were studied in single and double loss-of-function mouse mutants. Gsh2 gene function was found to be essential to maintain the molecular identity of early striatal progenitors and in its absence the ventral telencephalic regulatory genes Mash1 and Dlx are lost from most of the striatal germinal zone. In their place, the dorsal regulators, Pax6, neurogenin 1 and neurogenin 2 are found ectopically. Conversely, Pax6 is required to maintain the correct molecular identity of cortical progenitors. In its absence, neurogenins are lost from the cortical germinal zone and Gsh2, Mash1 and Dlx genes are found ectopically. These reciprocal alterations in cortical and striatal progenitor specification lead to the abnormal development of the cortex and striatum observed in Pax6 (small eye) and Gsh2 mutants, respectively. In support of this, double homozygous mutants for Pax6 and Gsh2 exhibit significant improvements in both cortical and striatal development compared with their respective single mutants. Taken together, these results demonstrate that Pax6 and Gsh2 govern cortical and striatal development by regulating genetically opposing programs that control the expression of each other as well as the regionally expressed developmental regulators Mash1, the neurogenins and Dlx genes in telencephalic progenitors.

BDV-syndrome: An emerging syndrome with profound obesity and neurodevelopmental delay resembling Prader-Willi syndrome

2021 ◽  
Author(s):  
Elisabeth Bosch ◽  
Moritz Hebebrand ◽  
Bernt Popp ◽  
Theresa Penger ◽  
Bettina Behring ◽  
...  
Keyword(s):  
Clinical Features ◽  
Large Scale ◽  
Hypogonadotropic Hypogonadism ◽  
Computational Modelling ◽  
Prader Willi Syndrome ◽  
Loss Of Function ◽  
Human Phenotype ◽  
Neurodevelopmental Delay ◽  
Missense Variants ◽  
Severely Obese

Abstract Context CPE encodes carboxypeptidase E, an enzyme which converts proneuropeptides and propeptide hormones to bioactive forms. It is widely expressed in the endocrine and central nervous system. To date, four individuals from two families with core clinical features including morbid obesity, neurodevelopmental delay and hypogonadotropic hypogonadism, harbouring biallelic loss-of-function CPE variants, were reported. Objective We describe four affected individuals from three unrelated consanguineous families, two siblings of Syrian, one of Egyptian and one of Pakistani descent, all harbouring novel homozygous CPE loss-of-function variants. Methods After excluding Prader-Willi syndrome, exome sequencing was performed in both Syrian siblings. The variants identified in the other two individuals were reported as research variants in a large scale exome study and in ClinVar database. Computational modelling of all possible missense alterations allowed assessing CPE tolerance to missense variants. Results All affected individuals were severely obese with neurodevelopmental delay and other endocrine anomalies. Three individuals from two families shared the same CPE homozygous truncating variant c.361C>T, p.(Arg121*), while the fourth carried the c.994del, p.(Ser333Alafs*22) variant. Comparison of clinical features with previously described cases and standardization according to the Human Phenotype Ontology indicated a recognisable clinical phenotype, which we termed Blakemore-Durmaz-Vasileiou (BDV) syndrome. Computational analysis indicated high conservation of CPE domains and intolerance to missense changes. Conclusions Biallelic truncating CPE variants are associated with BDV syndrome, a clinically recognisable monogenic recessive syndrome with childhood-onset obesity, neurodevelopmental delay, hypogonadotropic hypogonadism and hypothyroidism. BDV syndrome resembles Prader-Willi syndrome. Our findings suggested that missense variants may also be clinically relevant.

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