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Background

Mutations of the NR5A1 gene encoding steroidogenic factor-1 have been reported in association with a wide spectrum of 46,XY DSD (Disorder of Sex Development) phenotypes including severe forms of hypospadias.

Methodology/Principal Findings

We evaluated the frequency of NR5A1 gene mutations in a large series of patients presenting with 46,XY DSD and hypospadias. Based on their clinical presentation 77 patients were classified either as complete or partial gonadal dysgenesis (uterus seen at genitography and/or surgery, n = 11), ambiguous external genitalia without uterus (n = 33) or hypospadias (n = 33). We identified heterozygous NR5A1 mutations in 4 cases of ambiguous external genitalia without uterus (12.1%; p.Trp279Arg, pArg39Pro, c.390delG, c140_141insCACG) and a de novo missense mutation in one case with distal hypospadias (3%; p.Arg313Cys). Mutant proteins showed reduced transactivation activity and mutants p.Arg39Pro and p.Arg313Cys did not synergize with the GATA4 cofactor to stimulate reporter gene activity, although they retained their ability to physically interact with the GATA4 protein.

Conclusions/Significance

Mutations in NR5A1 were observed in 5/77 (6.5%) cases of 46,XY DSD including hypospadias. Excluding the cases of 46,XY gonadal dysgenesis the incidence of NR5A1 mutations was 5/66 (7.6%). An individual with isolated distal hypopadias carried a de novo heterozygous missense mutation, thus extending the range of phenotypes associated with NR5A1 mutations and suggesting that this group of patients should be screened for NR5A1 mutations.  相似文献   

4.

Background

46,XY disorders of sex development (46,XY DSD) are genetically heterogeneous conditions. Recently, a few submicroscopic genomic rearrangements have been reported as novel genetic causes of 46,XY DSD.

Methodology/Principal Findings

To clarify the role of cryptic rearrangements in the development of 46,XY DSD, we performed array-based comparative genomic hybridization analysis for 24 genetic males with genital abnormalities. Heterozygous submicroscopic deletions were identified in three cases (cases 1–3). A ∼8.5 Mb terminal deletion at 9p24.1–24.3 was detected in case 1 that presented with complete female-type external genitalia and mental retardation; a ∼2.0 Mb interstitial deletion at 20p13 was identified in case 2 with ambiguous external genitalia and short stature; and a ∼18.0 Mb interstitial deletion at 2q31.1–32 was found in case 3 with ambiguous external genitalia, mental retardation and multiple anomalies. The genital abnormalities of case 1 could be ascribed to gonadal dysgenesis caused by haploinsufficiency of DMRT1, while those of case 3 were possibly associated with perturbed organogenesis due to a deletion of the HOXD cluster. The deletion in case 2 affected 36 genes, none of which have been previously implicated in sex development.

Conclusions/Significance

The results indicate that cryptic genomic rearrangements constitute an important part of the molecular bases of 46,XY DSD and that submicroscopic deletions can lead to various types of 46,XY DSD that occur as components of contiguous gene deletion syndromes. Most importantly, our data provide a novel candidate locus for 46,XY DSD at 20p13.  相似文献   

5.

Background

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is the most common presentation of a disorder of sex development (DSD) in genetic females. A report of prenatal growth retardation in cases of 46,XY DSD, coupled with observations of below-optimal final height in both males and females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, prompted us to investigate prenatal growth in the latter group. Additionally, because girls with congenital adrenal hyperplasia are exposed to increased levels of androgens in the absence of a male sex-chromosome complement, the presence or absence of typical sex differences in growth of newborns would support or refute a hormonal explanation for these differences.

Methods

In total, 105 newborns with congenital adrenal hyperplasia were identified in our database. Gestational age (weeks), birth weight (kg), birth length (cm) and parental heights (cm) were obtained. Mid-parental height was considered in the analyses.

Results

Mean birth weight percentile for congenital adrenal hyperplasia was 49.26%, indicating no evidence of a difference in birth weight from the expected standard population median of 50th percentile (P > 0.05). The expected sex difference in favor of heavier males was not seen (P > 0.05). Of the 105 subjects, 44 (27%; 34 females, 10 males) had birth length and gestational age recorded in their medical chart. Mean birth length for this subgroup was 50.90 cm (63rd percentile), which differed from the expected standard population median of 50th percentile (P = 0.0082). The expected sex difference in favor of longer males was also not seen (P > 0.05).

Conclusion

The prenatal growth retardation patterns reported in cases of 46,XY disorders of sex development do not generalize to people with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Sex differences in body weight and length typically seen in young infants were not seen in the subjects who participated in this study. We speculate that these differences were ameliorated in this study because of increased levels of prenatal androgens experienced by the females infants.  相似文献   

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BACKGROUND:

Determination of sex is the result of cascade of molecular events that cause undifferentiated bipotential gonad to develop as a testis or an ovary. A series of genes such as SRY, steroidogenic factor-1 (SF1), AR, SRD5 α, Desert hedgehog (DHH) etc., have been reported to have a significant role in development of sex in the fetus and secondary sexual characteristics at the time of puberty. Recently, mitogen activated protein kinase kinase kinase 1 (MAP3K1) gene was found to be associated with 46, XY disorders of sex development (DSD).

AIM:

The present study is focused to identify mutations in MAP3K1 gene in the cohort of 10 Indian patients with 46,XY DSD including one family with two affected sisters. These patients were already screened for SRY, SF1 and DHH gene, but no mutation was observed in any of these genes.

MATERIALS AND METHODS:

The entire coding regions of MAP3K1 were amplified and sequenced using the gene specific primers.

RESULTS AND DISCUSSIONS:

Sequence analysis of MAP3K1 gene has revealed four variants including one missense, two silent and one deletion mutation. The missense mutation p.D806N was observed in four patients with hypospadias. Two patients showed the presence of silent mutation p.Q1028Q present in exon 14. Another silent mutation p.T428T was observed in a patient with gonadal dysgenesis. We have also observed one deletion mutation p. 942insT present in two patients. The pathogenicity of the missense mutation p.D806N was carried out using in-silico approach. Sequence homology analysis has revealed that the aspartate at 806 was found to be well-conserved across species, indicated the importance of this residue. The score for polyphen analysis of this mutation was found to be 0.999 indicating to be pathogenic mutation. Since, p.D806N mutation was found to be important residue; it might contribute to sexual development. We have reported the presence of mutations/polymorphism in MAP3K1 gene. All the mutations were found to be polymorphism upon comparing to single nucleotide polymorphism database. However, in-silico analysis of the missense mutation revealed to be a pathogenic mutation.  相似文献   

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46,XY pure gonadal dysgenesis, first described in 1955 by Swyer, results from testicular tissue loss during the first 8 weeks of fetal life, a critical period for male differentiation. We describe a case of an 18 years old patient presented to us with a chief complain of primary amenorrhea. Chromosomal analysis revealed a 46,XY karyotype. A molecular investigation was undertaken in an attempt to determine mutations in SRY and AR genes through DNA sequencing. Mutations were shown to be absent. The molecular basis of Swyer syndrome is still unknown, although the presence of mutations in testicular organizing genes downstream of SRY is still to rule out. The patient, who is considered as female, was placed on estrogen replacement therapy, while bilateral prophylactic laparoscopic gonadectomy was programmed due to the high prevalence of gonadal tumors in this syndrome. No signs of malignance were detected in the gonadal tissue, which predicts that an intact SRY gene is usually, but not always, not related to the formation of malignancies like dysgeminomas or gonadoblastomas.  相似文献   

9.

BACKGROUND:

Primary amenorrhea is defined as the absence of menstruation and secondary sexual characteristics in phenotypic women aged 14 years or older. Hormonal disorders are main causes of primary amenorrhea. Common hormonal cause of primary amenorrhea includes pituitary dysfunction and absent ovarian function. The aim of this study was to estimate the incidence and types of chromosomal abnormalities in patients with primary amenorrhea in Egypt.

MATERIALS AND METHODS:

Chromosomal analysis and hormonal assay were carried out on 223 patients with primary amenorrhea that were referred from different parts of Egypt to Cytogenetic laboratory of Genetic Unit, Children Hospital Mansoura University, from July 2008 to December 2010. FISH technique was carried out in some of cases to more evaluation.

RESULTS:

The frequency of chromosomal abnormalities was 46 (20.63%) in primary amenorrhea patients. The chromosomal abnormalities can be classified into four main types. (1) The numerical abnormalities of the X chromosome were detected in 23 (50 %). (2) Structural abnormalities of the X chromosome were detected in 11 (23.91%). (3) Mosaicism of X chromosome was found in 10 (21.74%). (4) Male karyotype 46, XY was presented in 2 (4.35%).

CONCLUSION:

The present study showed that karyotype and FISH are necessary to detect the causes of primary amenorrhea. This study also revealed the incidence of chromosomal abnormalities in women with primary amenorrhea in Egypt is similar to that reported in previous literatures.  相似文献   

10.

AIM:

This study aims at evaluating the chromosomal abnormalities and deoxyribonucleic acid (DNA) damage in cases with primary amenorrhea by karyotyping and comet assay.

STUDY DESIGN:

A total of 30 cases of primary amenorrhea were recruited. Secondary sexual characters were assessed by Tanner staging. Chromosomal analysis was performed by conventional phytohemagglutinin stimulated lymphocyte cell culture technique. Alkaline version of comet assay was used to evaluate DNA damage.

RESULTS:

The chromosomal pattern of 20 subjects (66.7%) was found to be normal (46,XX). Two subjects had 46,XY pattern and eight subjects had Turner syndrome (45,X or 45,X/46,XX). The comet parameters were found to be increased among subjects with 45,X monosomy, when compared to the rest of the study group and also in subjects with Tanner stage 1 when compared to stage 2.

CONCLUSION:

Comet assay revealed increased DNA damage in cases with 45,X monosomy, compared with subjects with 46,XX and 46,XY karyotype, which correlated with clinical features.  相似文献   

11.
Investigations of humans with disorders of sex development (DSDs) resulted in the discovery of many of the now-known mammalian sex-determining genes, including SRY, RSPO1, SOX9, NR5A1, WT1, NR0B1, and WNT4. Here, the locus for an autosomal sex-determining gene was mapped via linkage analysis in two families with 46,XY DSD to the long arm of chromosome 5 with a combined, multipoint parametric LOD score of 6.21. A splice-acceptor mutation (c.634-8T>A) in MAP3K1 segregated with the phenotype in the first family and disrupted RNA splicing. Mutations were demonstrated in the second family (p.Gly616Arg) and in two of 11 sporadic cases (p.Leu189Pro, p.Leu189Arg)-18% prevalence in this cohort of sporadic cases. In cultured primary lymphoblastoid cells from family 1 and the two sporadic cases, these mutations altered the phosphorylation of the downstream targets, p38 and ERK1/2, and enhanced binding of RHOA to the MAP3K1 complex. Map3k1 within the syntenic region was expressed in the embryonic mouse gonad prior to, and after, sex determination. Thus, mutations in MAP3K1 that result in 46,XY DSD with partial or complete gonadal dysgenesis implicate this pathway in normal human sex determination.  相似文献   

12.

Background

Klinefelter syndrome (KS), caused by XXY karyotype, is characterized by low testosterone, infertility, cognitive deficits, and increased prevalence of health problems including obesity and diabetes. It has been difficult to separate direct genetic effects from hormonal effects in human studies or in mouse models of KS because low testosterone levels are confounded with sex chromosome complement.

Methods

In this study, we present the Sex Chromosome Trisomy (SCT) mouse model that produces XXY, XYY, XY, and XX mice in the same litters, each genotype with either testes or ovaries. The independence of sex chromosome complement and gonadal type allows for improved recognition of sex chromosome effects that are not dependent on levels of gonadal hormones. All mice were gonadectomized and treated with testosterone for 3 weeks. Body weight, body composition, and motor function were measured.

Results

Before hormonal manipulation, XXY mice of both sexes had significantly greater body weight and relative fat mass compared to XY mice. After gonadectomy and testosterone replacement, XXY mice (both sexes) still had significantly greater body weight and relative fat mass, but less relative lean mass compared to XY mice. Liver, gonadal fat pad, and inguinal fat pad weights were also higher in XXY mice, independent of gonadal sex. In several of these measures, XX mice also differed from XY mice, and gonadal males and females differed significantly on almost every metabolic measure. The sex chromosome effects (except for testis size) were also seen in gonadally female mice before and after ovariectomy and testosterone treatment, indicating that they do not reflect group differences in levels of testicular secretions. XYY mice were similar to XY mice on body weight and metabolic variables but performed worse on motor tasks compared to other groups.

Conclusions

We find that the new SCT mouse model for XXY and XYY recapitulates features found in humans with these aneuploidies. We illustrate that this model has significant promise for unveiling the role of genetic effects compared to hormonal effects in these syndromes, because many phenotypes are different in XXY vs. XY gonadal female mice which have never been exposed to testicular secretions.
  相似文献   

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Despite the identification of an increasing number of genes involved in sex determination and differentiation, no cause can be attributed to most cases of 46, XY gonadal dysgenesis, approximately 20% of 46, XX males and the majority of subjects with 46, XX true hermaphroditism. Perhaps the most interesting candidate for involvement in sexual development is SOX3, which belongs to the same family of proteins (SOX) as SRY and SOX9, both of which are involved in testis differentiation. As SOX3 is the most likely evolutionary precursor to SRY, it has been proposed that it has retained a role in testis differentiation. Therefore, we screened the coding region and the 5 and 3 flanking region of the SOX3 gene for mutations by means of single-stranded conformation polymorphism and heteroduplex analysis in eight subjects with 46, XX sex reversal (SRY negative) and 25 subjects with 46, XY gonadal dysgenesis. Although no mutations were identified, a nucleotide polymorphism (1056C/T) and a unique synonymous nucleotide change (1182A/C) were detected in a subject with 46, XY gonadal dysgenesis. The single nucleotide polymorphism had a heterozygosity rate of 5.1% (in a control population) and may prove useful for future X-inactivation studies. The absence of SOX3 mutations in these patients suggests that SOX3 is not a cause of abnormal male sexual development and might not be involved in testis differentiation.An erratum to this article can be found at  相似文献   

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Human sexual determination is initiated by a cascade of genes that lead to the development of the fetal gonad. Whereas development of the female external genitalia does not require fetal ovarian hormones, male genital development requires the action of testicular testosterone and its more potent derivative dihydrotestosterone (DHT). The "classic" biosynthetic pathway from cholesterol to testosterone in the testis and the subsequent conversion of testosterone to DHT in genital skin is well established. Recently, an alternative pathway leading to DHT has been described in marsupials, but its potential importance to human development is unclear. AKR1C2 is an enzyme that participates in the alternative but not the classic pathway. Using a candidate gene approach, we identified AKR1C2 mutations with sex-limited recessive inheritance in four 46,XY individuals with disordered sexual development (DSD). Analysis of the inheritance of microsatellite markers excluded other candidate loci. Affected individuals had moderate to severe undervirilization at birth; when recreated by site-directed mutagenesis and expressed in bacteria, the mutant AKR1C2 had diminished but not absent catalytic activities. The 46,XY DSD individuals also carry a mutation causing aberrant splicing in AKR1C4, which encodes an enzyme with similar activity. This suggests a mode of inheritance where the severity of the developmental defect depends on the number of mutations in the two genes. An unrelated 46,XY DSD patient carried AKR1C2 mutations on both alleles, confirming the essential role of AKR1C2 and corroborating the hypothesis that both the classic and alternative pathways of testicular androgen biosynthesis are needed for normal human male sexual differentiation.  相似文献   

15.

Background

Luteinizing hormone-releasing hormone (LH-RH) agonists are the standard for androgen deprivation therapy (ADT) in prostate cancer (PCa) patients. Current guidelines recommend serum testosterone measurement to assess the efficacy of ADT and to define castration resistance. However, serum testosterone does not reflect the exclusive effect of castration due to its extratesticular production. The aim of this study is to analyze if serum LH reflects better than serum testosterone the activity of LH-RH agonists.

Methods

Serum LH and serum testosterone were measured with chemiluminescent immunoassay (CLIA) in a cohort study of 1091 participants: 488 PCa patients “on LH-RH agonists”, 303 “off LH-RH agonist” in whom LH-RH agonists were withdrawn, and 350 men with PCa suspicion “no LH-RH agonist” who never received LH-RH agonists. In a validation cohort of 147 PCa patients, 124 on “LH-RH agonists” and 19 “off LH-RH agonists”, serum testosterone was also measured with liquid chromatography and tandem mass spectrometry (LC MSMS).

Results

The area under the curve (AUC) to distinguish patients “on versus off LH-RH agonists” was 0.997 for serum LH and 0.740 for serum testosterone, P < 0.001. The 97.5 percentile of serum LH in patients “on LH-RH agonists” was 0.97 U/L, been the most efficient threshold 1.1 U/L. The AUCs for serum LH, testosterone measured with CLIA and with LC MSMS, in the validation cohort, were respectively 1.000, 0.646 and 0.814, P < 0.001. The efficacy to distinguish patients “on versus off LH-RH agonists” was 98.6%, 78.3%, and 89.5% respectively, using 1.1 U/L as threshold for serum LH and 50 ng/dL for serum testosterone regardless the method.

Conclusions

Serum LH is more accurate than serum testosterone regardless the method, to distinguish patients “on versus off LH-RH agonists”. The castrate level of serum LH is 1.1 U/l. These findings suggest that assessment of LH-RH agonist efficacy and castration resistance definition should be reviewed.
  相似文献   

16.

Introduction

The diagnosis of acquired hypogonadism is still an important issue for laboratory medicine. Hypogonadism is defined as a sustained decrease of total testosterone confirmed by the biochemistry laboratory and total testosterone measurement is proposed as the initial step in the investigation of hypogonadism. If TT is over 12 nmol/l, the probability of hypogonadism is considered low and it is suggested that patients be referred to others methods of investigation. Only a small percentage of men aged 50 and over are treated for hypogonadism. Seventy percent of men investigated for hypogonadism have a TT of over 12 nmol/l and there is an unpredictable increase of SHBG during this period, reducing the bioavailability of circulating testosterone. The hypothalamic-pituitary gonadal axis is modified with age and contributes to hypogonadism. The efficacy of biochemical investigation of hypogonadism needs to be reassessed.

Materials and methods

Total testosterone and LH were measured on the Centaur immunoanalyser (Siemens) and SHBG was analysed on the Immulite 2000 (Siemens). Bioavailable testosterone was calculated using the formula provided by ISSAM.

Results

Using the algorithm based on TT, only 27.9% of men would have been investigated for hypogonadism. Of the 638 patients considered as normal, 325 showed an index of hypothalamic-pituitary gonadal axis stimulation and possible hypogonadism, revealed by an elevated LH. In these patients with TT superior to 12 nmol/l and a LH superior to 7 UI/l, SHBG level was at the upper limit of or over the reference range. No correlation was observed between calculated BT and the abnormal LH level found in these patients. Calculated BT was not considered a good marker of hypogonadism for these patients.

Conclusion

Elevated LH is a biochemical marker of hypogonadism and should be interpreted in the context of stimulation of the hypothalamic-pituitary gonadal axis. Based on our data, an initial step in the investigation of hypogonadism based only on TT does not seem suitable for the identification of all patients who might experience hypogonadism. A complete investigation should be offered to all patients with clinical evidence of hypogonadism whatever their TT level. In patients who might benefit from hormonal treatment, calculated BT should be interpreted with caution. A definition of hypogonadism based on TT does not seem appropriate and a new definition based on bioavailable testosterone and the hypothalamopituitary gonadal axis should be considered.  相似文献   

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The first step of male differentiation is the testis determination which is genetically controled. The key role of SRY gene is now established. However, a number of clinical and genetic data favoured the role of other genes taking place upstream or downstream SRY. Most of 46, XX males possess a translocated SRY gene and thus develop testis, but SRY gene is not found in 10% of such patients. Likewise, the molecular study of 46, XY females participated in the identification of SRY as testis determining factor, but 80% of XY gonadal dysgenesis are not explained by an abnormality of SRY gene. Several clinical situations permitted to suspect the role of autosomal (chromosome 1, 9, 10 17 …) and X chromosome loci in the pathology of sex determination. Some recent works concern, in particular, the testis determining factor of the X chromosome (TDF-X) that could act as a repressor of the testis differentiation. In conclusion, molecular mechanisms of sexual determination appear to be much complex, involving probably several genes in a pathway that remain to be elucidated.  相似文献   

19.

Background

Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping.

Results

Chromosome painting reveals a meiotic chain of nine sex chromosomes in the male echidna and establishes their order in the chain. Two of those differ from those in the platypus, three of the platypus sex chromosomes differ from those of the echidna and the order of several chromosomes is rearranged. Comparative gene mapping shows that, in addition to bird autosome regions, regions of bird Z chromosomes are homologous to regions in four platypus X chromosomes, that is, X1, X2, X3, X5, and in chromosome Y1.

Conclusion

Monotreme sex chromosomes are easiest to explain on the hypothesis that autosomes were added sequentially to the translocation chain, with the final additions after platypus and echidna divergence. Genome sequencing and contig anchoring show no homology yet between platypus and therian Xs; thus, monotremes have a unique XY sex chromosome system that shares some homology with the avian Z.  相似文献   

20.
Patients with Disorders of Sex Development (DSD), especially those with gonadal dysgenesis and hypovirilization are at risk of developing malignant type II germ cell tumors/cancer (GCC) (seminoma/dysgerminoma and nonseminoma), with either carcinoma in situ (CIS) or gonadoblastoma (GB) as precursor lesion. In 10-15% of 46,XY gonadal dysgenesis cases (i.e., Swyer syndrome), SRY mutations, residing in the HMG (High Mobility Group) domain, are found to affect nuclear transport or binding to and bending of DNA. Frasier syndrome (FS) is characterized by gonadal dysgenesis with a high risk for development of GB as well as chronic renal failure in early adulthood, and is known to arise from a splice site mutation in intron 9 of the Wilms' tumor 1 gene (WT1). Mutations in SRY as well as WT1 can lead to diminished expression and function of SRY, resulting in sub-optimal SOX9 expression, Sertoli cell formation and subsequent lack of proper testicular development. Embryonic germ cells residing in this unfavourable micro-environment have an increased risk for malignant transformation. Here a unique case of a phenotypically normal female (age 22 years) is reported, presenting with primary amenorrhoea, later diagnosed as hypergonadotropic hypogonadism on the basis of 46,XY gonadal dygenesis with a novel missense mutation in SRY. Functional in vitro studies showed no convincing protein malfunctioning. Laparoscopic examination revealed streak ovaries and a normal, but small, uterus. Pathological examination demonstrated bilateral GB and dysgerminoma, confirmed by immunohistochemistry. Occurrence of a delayed progressive kidney failure (focal segmental glomerular sclerosis) triggered analysis of WT1, revealing a pathogenic splice-site mutation in intron 9. Analysis of the SRY gene in an additional five FS cases did not reveal any mutations. The case presented shows the importance of multi-gene based diagnosis of DSD patients, allowing early diagnosis and treatment, thus preventing putative development of an invasive cancer.  相似文献   

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