Mutation Of Luteinizing Hormone Receptor Research Articles

Testotoxicosis without Testicular Mass: Revealed by Peripheral Precocious Puberty and Confirmed by Somatic LHCGR Gene Mutation

ABSTRACTPurpose: Testotoxicosis is an autosomal dominant form of limited gonadotropin-independent precocious puberty in boys. It is caused by a heterozygous constitutively activating mutation of the LHCGR gene encoding the luteinizing/hormone receptor (LHR). Some twenty mutations of the LHCGR gene have been reported. Most of them are constitutive mutations isolated from blood leukocyte DNA, although others are somatic, found only in testicular tumoural tissue. In all the previously reported cases of these somatic mutations, the tumour, whether a nodular Leydig cell adenoma or hyperplasia, was easily visible on testicular ultrasonography. The aim of this study was to describe an unusual presentation of a patient with the clinical and hormonal characteristics of testotoxicosis but no well-circumscribed lesion at testicular ultrasonography.Materials and Methods: Molecular analysis of the LHCGR gene was performed by direct sequencing of DNA extracted from peripheral leucocytes and testicular biopsy.Results: Molecular analysis didn’t find any LHR mutation in blood, whereas it revealed for the first time a somatic D578H mutation in testicular tissue despite no evidence of a nodular aspect at testis ultrasonography.Conclusions: This observation underlines the need to look for a somatic LHCGR gene mutation from the testicular biopsies of all boys with testotoxicosis with no constitutive LHCGR gene mutation identified from blood DNA, even in the absence of circumscribed testicular lesion at ultrasonography. In addition, based on the known link between LHR mutations and testicular tumourigenesis, yearly ultrasound monitoring of the testes should be considered for these patients.

LHCGR Gene Analysis in Girls with Non-Classic Central Precocious Puberty.

Luteinizing hormone (LH) is a useful parameter in diagnosing precocious puberty. The pubertal response of serum LH to a GnRH stimulation test is varied, and clinical symptoms of precocious puberty are sometimes disproportionate with serum LH concentrations. Many patients present in a state of precocious puberty that advances rapidly, but the post-GnRH peak LH remains prepubertal. LH receptor mutations are suspected of involvement in the non-classic type of central precocious puberty (CPP). To examine the association between LHCGR polymorphism and non-classic CPP in subjects exhibiting a peak LH<5 IU/L on a GnRH stimulation test. In total, 102 girls with non-classic CPP and 100 normal adult women were enrolled. All subjects underwent LHCGR gene analysis by the Sanger method, and patients and controls were compared. Auxological data and gonadotropin concentrations were analyzed in the 102 patients. Of these patients, 75 completed GnRH agonist treatment, and the treatment outcomes were analyzed. A total of seven variants were identified, including two missense mutations (g.48698754 G/A and g.48688613 G/A) that were found in the patient group (no patients contained both mutations). In silico analysis of these missense mutations suggested the possibility of damaging the LHCGR. However, no significant association was found between the identified LHCGR variants and non-classic CPP. GnRH agonist treatment decreased bone age advancement and increased predicted adult height. LHCGR gene polymorphisms do not appear to be a major causative factor for the relatively low concentration of LH in patients with non-classic CPP. GnRH agonist treatment improved clinical parameters in these patients.

Study on a pedigree with Leydig cell hypoplasia caused by novel mutation of luteinizing hormone receptor

Objective To investigate a Chinese pedigree suffering from Leydig cell hypoplasia ( LCH) based on clinical data and genetic diagnosis. Methods The patient was diagnosed by means of clinical data, hormone profiles, and human chorionic gonadotropin ( hCC) test. The luteinizing hormone/chorionic gonadotropin receptor(LHCGR) gene of the patient and family members was amplified and sequenced. Results The patient presented with male pseudohermaphroditism, low level of testosterone, which did not respond to hCG. Genetic analysis of the LHCGR revealed two novel mutations: a missense mutation located in exon 5, resulting in Ile replaced by Thr in the extracellular domain; and a splice site mutation in the 3' terminal of intron 6( IVS6-3 C→A). Proband's sister (46, XX) who lacked clinical manifestations showed the identical genotype with the patient. Conclusions A mutation in the consensus sequence of 3' splice site, in addition to a missense mutation (Ile 152Thr)in the extracellular ligand-binding domain is the cause of inactivation of the LHCGR gene in patient with Leydig cell hypoplasia. Key words: Luteinizing hormone/chorionic gonadotropin receptor; Male pseudohermaphroditism; Leydig cell hypoplasia

Asp330 and Tyr331 in the C-terminal Cysteine-rich Region of the Luteinizing Hormone Receptor Are Key Residues in Hormone-induced Receptor Activation

The luteinizing hormone (LH) receptor plays an essential role in male and female gonadal function. Together with the follicle-stimulating hormone (FSH) and thyroid stimulating hormone (TSH) receptors, the LH receptor forms the family of glycoprotein hormone receptors. All glycoprotein hormone receptors share a common modular topography, with an N-terminal extracellular ligand binding domain and a C-terminal seven-transmembrane transduction domain. The ligand binding domain consists of 9 leucine-rich repeats, flanked by N- and C-terminal cysteine-rich regions. Recently, crystal structures have been published of the extracellular domains of the FSH and TSH receptors. However, the C-terminal cysteine-rich region (CCR), also referred to as the "hinge region," was not included in these structures. Both structure and function of the CCR therefore remain unknown. In this study we set out to characterize important domains within the CCR of the LH receptor. First, we mutated all cysteines and combinations of cysteines in the CCR to identify the most probable disulfide bridges. Second, we exchanged large parts of the LH receptor CCR by its FSH receptor counterparts, and characterized the mutant receptors in transiently transfected HEK 293 cells. We zoomed in on important regions by focused exchange and deletion mutagenesis followed by alanine scanning. Mutations in the CCR specifically decreased the potencies of LH and hCG, because the potency of the low molecular weight agonist Org 41841 was unaffected. Using this unbiased approach, we identified Asp(330) and Tyr(331) as key amino acids in LH/hCG mediated signaling.

Orthotopic transplantation of LH receptor knockout and wild-type ovaries

Luteinizing hormone (LH) receptor knockout animals have an ovarian failure due to an arrest in folliculogenesis at the antral stage. As a result, the animals have an infertility phenotype. The present study was undertaken to determine whether this phenotype could be reversed by orthotopic transplantation of wild-type ovaries. The results revealed that transplanting wild-type ovaries into null animals did not result in resumption of estrus cycles. Although the number of different types of follicles increased, none progressed to ovulation. The serum hormone profiles improved, reflecting the ovarian changes. The wild-type animals with null ovaries also failed to cycle and their ovaries and serum hormone levels were more like null animals with their own ovaries. Although the lack of rescue of null ovaries placed into wild-type animals was predicted, the failure of wild-type ovaries placed in null animals was not, which could be due to chronic exposure of transplanted tissue to high circulating LH levels and also possibly due to altered internal milieu in null animals. These findings may have implications for potential future considerations of grafting normal donor ovaries into women who have an ovarian failure resulting from inactivating LH receptor mutations.

Consequences of targeted inactivation of LH receptors

The inactivation of luteinizing hormone (LH) receptors was neither lethal nor it had any effect on sex differentiation. However, it dramatically reduced the growth and development of gonads and the reproductive tract. As a result, both female and male animals were infertile. Serum LH levels were dramatically elevated, follicle stimulating hormone (FSH) levels moderately elevated in both sexes, estradiol and progesterone levels partially decreased in females, testosterone levels dramatically decreased and estradiol levels moderately increased in males. The knockout of LH receptors had no effect on gonadal FSH receptors in both sexes, progesterone receptors in females and androgen receptors in males. However, estrogen receptor ERα and steroidogenic acute regulatory protein decreased and ERβ increased in both sexes. cDNA expression array analyses revealed that testes were affected more than ovaries and more genes showed an increase rather than a decrease in testes. The affected genes came from many unexpected families. Both null females and males had a decreased density of femur and became obese with age. The ovarian failure in knockout animals could not be reversed by estradiol/progesterone replacement therapy or by PMSG and human chorionic gonadotropin (hCG) injections. Although, testosterone replacement therapy of 30–60-day old null males partially improved spermatogenesis, the animals still remained infertile. A single testosterone injection on postnatal day 1 followed by 21–45-day testosterone replacement therapy beginning at 30 days of age, however, restored fertility. Studies showed that uterus of null animals could not initiate pregnancy even though the size and morphology were greatly improved by estradiol and progesterone replacement therapy. In general, non-gonadal phenotypes in null females and males were not completely reversed by hormone replacement therapy, suggesting that LH signaling could be important for their function. Heterozygous animals were indistinguishable from wild-type animals at 60 days of age. However, as they grew to about 1 year of age, they began to stop cycling, some became extremely obese, showed a decreased density of femur and all animals developed endometrial tumors with a cancer histology. LH receptor-knockout animals will be useful in advancing our present understanding on the importance of classical as well as non-classical actions of LH in the body, in advancing novel therapeutic uses of hCG, and in better understanding and rationalizing the consequences of inactivating type human LH receptor mutations.

Gonadotropin-Independent Precocious Puberty Due to Luteinizing Hormone Receptor Mutations in Brazilian Boys: A Novel Constitutively Activating Mutation in the First Transmembrane Helix

Gonadotropin-Independent Precocious Puberty Due to Luteinizing Hormone Receptor Mutations in Brazilian Boys: A Novel Constitutively Activating Mutation in the First Transmembrane Helix

Luteinizing hormone receptor mutations in disorders of sexual development and cancer

Luteinizing hormone receptor mutations in disorders of sexual development and cancer

Luteinizing Hormone Receptor Mutations in Disorders of Sexual Development and Cancer

Luteinizing Hormone Receptor Mutations in Disorders of Sexual Development and Cancer

Luteinizing hormone receptor mutations in disorders of sexual development and cancer.

Human male sexual development is regulated by chorionic gonadotropin (CG) and luteinizing hormone (LH). Aberrant sexual development caused by both activating and inactivating mutations of the human luteinizing hormone receptor (LHR) have been described. All known activating mutations of the LHR are missense mutations caused by single base substitution. The most common activating mutation is the replacement of Asp-578 by Gly due to the substitution of A by G at nucleotide position 1733. All activating mutations are present in exon 11 which encodes the transmembrane domain of the receptor. Constitutive activity of the LHR causes LH releasing hormone-independent precocious puberty in boys and the autosomal dominant disorder familial male-limited precocious puberty (FMPP). Both germline and somatic activating mutations of the LHR have been found in patients with testicular tumors. Activating mutations have no effect on females. The molecular genetics of the inactivating mutations of the LHR are more variable and include single base substitution, partial gene deletion, and insertion. These mutations are not localized and are present in both the extracellular and transmembrane domain of the receptor. Inactivation of the LHR gives rise to the autosomal recessive disorder Leydig cell hypoplasia (LCH) and male hypogonadism or male pseudohermaphroditism. Severity of the clinical phenotype in LCH patients correlates with the amount of residual activity of the mutated receptor. Females are less affected by inactivating mutation of the LHR. Symptoms caused by homozygous inactivating mutation of the LHR include polycystic ovaries and primary amenorrhea.

Luteinizing Hormone Receptor Mutations in Disorders of Sexual Development and Cancer

Human male sexual development is regulated by chorionic gonadotropin (CG) and luteinizing hormone (LH). Aberrant sexual development caused by both activating and inactivating mutations of the human luteinizing hormone receptor (LHR) have been described. All known activating mutations of the LHR are missense mutations caused by single base substitution. The most common activating mutation is the replacement of Asp-578 by Gly due to the substitution of A by G at nucleotide position 1733. All activating mutations are present in exon 11 which encodes the transmembrane domain of the receptor. Constitutive activity of the LHR causes LH releasing hormone-independent precocious puberty in boys and the autosomal dominant disorder familial male-limited precocious puberty (FMPP). Both germline and somatic activating mutations of the LHR have been found in patients with testicular tumors. A ctivating mutations have no effect on females. The molecular genetics of the inactivating mutations of the LHR are more variable and include single base substitution, partial gene deletion, and insertion. These mutations are not localized and are present in both the extracellular and transmembrane domain of the receptor. Inactivation of the LHR gives rise to the autosomal recessive disorder Leydig cell hypoplasia (LCH) and male hypogonadism or male pseudohermaphroditism. Severity of the clinical phenotype in LCH patients correlates with the amount of residual activity of the mutated receptor.Females are less affected by inactivating mutation of the LHR. Symptoms caused by homozygous inactivating mutation of the LHR include polycystic ovaries and primary amenorrhea.

A limited repertoire of mutations of the luteinizing hormone (LH) receptor gene in familial and sporadic patients with male LH-independent precocious puberty.

Herein, we report mutation analysis of the LH receptor gene in 17 males with LH-independent precocious puberty, of which 8 were familial and 9 had a negative family history. A total of 7 different mutations (all previously reported) were detected in 12 patients. Among 10 European familial male-limited precocious puberty (FMPP) patients who had a LH receptor gene mutation, none had the Asp578Gly mutation, which is responsible for the vast majority of cases in the U.S. The restricted number of activating mutations of the LH receptor observed in this and other studies of FMPP strongly suggests that an activating phenotype is associated with very specific sites in the receptor protein. Clinical follow-up of the 5 patients who did not have LH receptor mutations shows that such cases most likely do not have true FMPP. LH receptor mutation analysis provides a sensitive tool for distinguishing true FMPP from other causes of early-onset LH-independent puberty in males.

A Novel Luteinizing Hormone Receptor Mutation in a Patient with Familial Male-Limited Precocious Puberty: Effect of the Size of a Critical Amino Acid on Receptor Activity

Familial male-limited precocious puberty (FMPP) is a form of luteinizing hormone-releasing hormone (LHRH)-independent isosexual precocious puberty caused by gain-of-function mutations of the luteinizing hormone/chorionic gonadotropin receptor (hLHR). The most common mutation is 1733 A>G, which causes substitution of Asp-578 by Gly. In this study, a male infant presented at the age of 20 months with accelerated sexual development was analyzed for the presence of activating mutations of the hLHR. Analysis of exon 11 of the hLHR gene by genomic polymerase chain reaction (PCR), asymmetric PCR, and dideoxy sequencing identified a single base substitution, 1734 T>A, which led to the replacement of Asp-578 by Glu. The same mutation was found in the mother. Expression of the mutated hLHR in HEK 293 cells demonstrated elevated basal levels of intracellular cAMP in the transfected cells confirming the constitutive activating nature of the mutated hLHR. A possible genotype-phenotype relationship of the hLHR mutations was examined by a comparison of thein vitroactivities of the hLHRs carrying the Asp578Gly, Asp578Tyr, Asp578Trp, and Asp578Glu mutations in HEK 293 cells. A positive correlation between the size of the substituting amino acid and the basal level of intracellular cAMP of cells expressing the mutated receptor was demonstrated.

Luteinizing hormone receptor mutations and sex differentiation.

Mutations in the luteinizing hormone (LH) receptor gene have been found in patients with abnormalities in their sexual differentiation. In this paper we review results obtained in the studies of these LH receptor mutations. Activating and inactivating mutations are discussed with respect to the mechanism of action of LH/human chorionic gonadotrophin but also in light of their impact of the present knowledge of the physiology of sex differentiation and gonadal function.

Luteinizing hormone receptor mutation in familial male precocious puberty: differences in the post-translational processing of the mutant receptor.

Luteinizing hormone receptor mutation in familial male precocious puberty: differences in the post-translational processing of the mutant receptor.