A novel DEAH-box helicase 37 mutation associated with differences of sex development

OBJECTIVE

To determine the genetic etiology of a family pedigree with two patients affected by differences of sex development (DSD).

METHODS

Assess the clinical characteristics of the patients and achieve exome sequencing results and in vitro functional studies.

RESULTS

The 15-year-old proband, raised as female, presented with delayed puberty and short stature associated with atypical genitalia. Hormonal profile showed hypergonadotrophic hypogonadism. Imaging studies revealed the absence of a uterus and ovaries. The karyotype confirmed a 46, XY pattern. Her younger brother presented with a micropenis and hypoplastic scrotum with non-palpable testis and hypospadias. Laparoscopic exploration was performed on the younger brother. Streak gonads were found and removed due to the risk of neoplastic transformation. Post-operative histopathology showed the co-existence of Wolffian and Müllerian derivatives. Whole-exome sequencing identified a novel mutation (c.1223C>T, p. Ser408Leu) in the Asp-Glu-Ala-His-box helicase 37 gene, which was found to be deleterious by in silico analysis. Segregation analysis of the variant displayed a sex-limited, autosomal dominant, maternal inheritance pattern. In vitro experiments revealed that the substitution of 408Ser by Leu caused decreased DHX37 expression both at the mRNA and protein levels. Moreover, the β-catenin protein was upregulated, and the p53 protein was unaltered by mutant DHX37.

CONCLUSIONS

We described a novel mutation (c.1223C>T, p. Ser408Leu) of the DHX37 gene associated with a Chinese pedigree consisting of two 46, XY DSD patients. We speculated that the underlying molecular mechanism might involve upregulation of the β-catenin protein.

Developmental exposure to real-life environmental chemical mixture programs a testicular dysgenesis syndrome-like phenotype in prepubertal lambs

Current declines in male reproductive health may, in part, be driven by anthropogenic environmental chemical (EC) exposure. Using a biosolids treated pasture (BTP) sheep model, this study examined the effects of gestational exposure to a translationally relevant EC mixture. Testes of 8-week-old ram lambs from mothers exposed to BTP during pregnancy contained fewer germ cells and had a greater proportion of Sertoli-cell-only seminiferous tubules. This concurs with previous published data from fetuses and neonatal lambs from mothers exposed to BTP. Comparison between the testicular transcriptome of biosolids lambs and human testicular dysgenesis syndrome (TDS) patients indicated common changes in genes involved in apoptotic and mTOR signalling. Gene expression data and immunohistochemistry indicated increased HIF1α activation and nuclear localisation in Leydig cells of BTP exposed animals. As HIF1α is reported to disrupt testosterone synthesis, these results provide a potential mechanism for the pathogenesis of this testicular phenotype, and TDS in humans.

Revisiting the hybridization processes in the Triatoma brasiliensis complex (Hemiptera, Triatominae): Interspecific genomic compatibility point to a possible recent diversification of the species grouped in this monophyletic complex

Triatomines are hematophagous insects of great epidemiological importance, since they are vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. Triatoma brasiliensis complex is a monophyletic group formed by two subspecies and six species: T. b. brasiliensis, T. b. macromelasoma, T. bahiensis, T. juazeirensis, T. lenti, T. melanica, T. petrocchiae and T. sherlocki. The specific status of several species grouped in the T. brasiliensis complex was confirmed from experimental crossing and analysis of reproductive barriers. Thus, we perform interspecific experimental crosses between T. lenti and other species and subspecies of the T. brasiliensis complex and perform morphological analysis of the gonads and cytogenetic analysis in the homeologous chromosomes of the hybrids of first generation (F1). Besides that, we rescue all the literature data associated with the study of reproductive barriers in this monophyletic complex of species and subspecies. For all crosses performed between T. b. brasiliensis, T. b. macromelasoma, T. juazeirensis and T. melanica with T. lenti, interspecific copulas occurred (showing absence of mechanical isolation), hybrids were obtained, none of the male hybrids presented the phenomenon of gonadal dysgenesis and 100% pairing between the chromosomes homeologous of the hybrids was observed. Thus, we demonstrate that there are no pre-zygotic reproductive barriers installed between T. lenti and the species and subspecies of the T. brasiliensis complex. In addition, we demonstrate that the hybrids obtained between these crosses have high genomic compatibility and the absence of gonadal dysgenesis. These results point to reproductive compatibility between T. lenti and species and subspecies of the T. brasiliensis complex (confirming its inclusion in the complex) and lead us to suggest a possible recent diversification of the taxa of this monophyletic group.

Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men

Male reproductive health has declined as indicated by increasing rates of cryptorchidism, i.e., undescended testis, poor semen quality, low serum testosterone level, and testicular cancer. Exposure to endocrine disrupting chemicals (EDCs) has been proposed to have a role in this finding. In utero exposure to antiandrogenic EDCs, particularly at a sensitive period of fetal testicular development, the so-called 'masculinization programming window (MPW)', can disturb testicular development and function. Low androgen effect during the MPW can cause both short- and long-term reproductive disorders. A concurrent exposure to EDCs may also affect testicular function or damage testicular cells. Evidence from animal studies supports the role of endocrine disrupting chemicals in development of male reproductive disorders. However, evidence from epidemiological studies is relatively mixed. In this article, we review the current literature that evaluated relationship between prenatal EDC exposures and anogenital distance, cryptorchidism, and congenital penile abnormality called hypospadias. We review also studies on the association between early life and postnatal EDC exposure and semen quality, hypothalamic-pituitary-gonadal axis hormone levels and testicular cancer.

The gene encoding the ketogenic enzyme HMGCS2 displays a unique expression during gonad development in mice

Disorders/differences of sex development (DSD) cause profound psychological and reproductive consequences for the affected individuals, however, most are still unexplained at the molecular level. Here, we present a novel gene, 3-hydroxy-3-methylglutaryl coenzyme A synthase 2 (HMGCS2), encoding a metabolic enzyme in the liver important for energy production from fatty acids, that shows an unusual expression pattern in developing fetal mouse gonads. Shortly after gonadal sex determination it is up-regulated in the developing testes following a very similar spatial and temporal pattern as the male-determining gene Sry in Sertoli cells before switching to ovarian enriched expression. To test if Hmgcs2 is important for gonad development in mammals, we pursued two lines of investigations. Firstly, we generated Hmgcs2-null mice using CRISPR/Cas9 and found that these mice had gonads that developed normally even on a sensitized background. Secondly, we screened 46,XY DSD patients with gonadal dysgenesis and identified two unrelated patients with a deletion and a deleterious missense variant in HMGCS2 respectively. However, both variants were heterozygous, suggesting that HMGCS2 might not be the causative gene. Analysis of a larger number of patients in the future might shed more light into the possible association of HMGCS2 with human gonadal development.

The Potential Synergic Effect of a Complex Pattern of Multiple Inherited Genetic Variants as a Pathogenic Factor for Ovarian Dysgenesis: A Case Report

Non-syndromic primary ovarian insufficiency due to ovarian dysgenesis in 46,XX patients is an uncommon finding in the general population, even though several monogenic variants have been reported as causative factors. Here, we describe a 15-year-old patient diagnosed with gonadal dysgenesis possibly due to the interaction of three potentially pathogenic variants of genes involved in ovarian maturation, namely factor in the germline alpha (FIGLA), newborn ovary homeobox-encoding (NOBOX) and nuclear receptor subfamily 5 group A member 1 (NR5A1). We also describe a different degree of residual ovarian function within the proband's family, whose female members carry one to three demonstrated variations in the aforementioned genes in a clinical spectrum potentially dependent on the number of alleles involved. Our results support the hypothesis that the severity of the clinical picture of the proband, resulting in complete ovarian dysgenesis, may be due to a synergic detrimental effect of inherited genetic variants.

Genome-wide identification, evolution of DNA methyltransferases and their expression during gonadal development in Nile tilapia

DNA methyltransferases (dnmts) are responsible for DNA methylation and play important roles in organism development. In this study, seven dnmts genes (dnmt1, dnmt2, dnmt3aa, dnmt3ab, dnmt3ba, dnmt3bb.1, dnmt3bb.2) were identified in Nile tilapia. Comprehensive analyses of dnmts were performed using available genome databases from representative animal species. Phylogenetic analysis revealed that the dnmts family were highly conserved in teleosts. Based on transcriptome data from eight adult tilapia tissues, the dnmts were found to be dominantly expressed in the head kidney, testis and ovary. Analyses of the gonadal transcriptome data in different developmental stages revealed that all dnmts were expressed in both ovary and testis, and four de novo dnmts (dnmt3aa, dnmt3ab, dnmt3bb.1, dnmt3bb.2) showed higher expression in the testis than in the ovary. Furthermore, during sex reversal induced by Fadrozole, the expression of these four de novo dnmts increased significantly in treated group compared to female control group. By in situ hybridization, the seven dnmts were found to be expressed mainly in phase I and II oocytes of the ovary and spermatocytes of the testis. When gonads were incubated with a methyltransferase inhibitor (5-AzaCdR) in vitro, the expression of dnmts genes were down-regulated significantly, while the expression of cyp19a1a (a key gene in female pathway) and dmrt1 (a key gene in male pathway) increased significantly. Our results revealed the conservation of dnmts during evolution and indicated a potential role of dnmts in epigenetic regulation of gonadal development.

Leydig cell clustering and Reinke crystal distribution in relation to hormonal function in adult patients with testicular dysgenesis syndrome (TDS) including cryptorchidism

OBJECTIVE

Testicular dysgenesis syndrome (TDS) comprises testicular germ cell cancer, cryptorchidism and some cases of male infertility and hypospadias, which can be linked to impairment of intrauterine gonadal development. Among histological signs of TDS, large Leydig cell (LC) clusters (micronodules) are frequently present. This study aimed to investigate possible associations of LC micronodules with the presence of Reinke crystals and hormonal function of LCs, the latter primarily reflected by serum concentrations of luteinising hormone (LH) and testosterone, in patients with TDS.

DESIGN

A retrospective study of 101 andrological patients with TDS (infertility with and without a history of cryptorchidism or presence of germ cell neoplasia in situ) and 20 controls with normal testis histology and LC-function. Archived testicular biopsies were re-evaluated for the presence of LC micronodules and Reinke crystals and the findings were correlated with testis size and serum concentrations of LH, follicle-stimulating hormone (FSH), testosterone, inhibin B, estradiol and sex hormone binding globulin (SHBG).

RESULTS

TDS patients with bilateral LC micronodules had significantly lower concentrations of LH, FSH and inhibin B, a lower testosterone/LH-ratio and smaller testis sizes compared to TDS-patients lacking this feature. Presence of LC micronodules was correlated with a lower number of Reinke crystals, while cryptorchid testes had a significantly higher number of crystals than normally descended TDS testes.

CONCLUSION

LC micronodules appear to be a compensatory mechanism caused by androgenic failure and are presumably driven by high concentrations of LH. A relative paucity of Reinke crystals in LCs within micronodules in normally descended TDS testes may be a feature of recently renewed immature Leydig cells. The increased number of Reinke crystals in LCs in testes that were either undescended at birth or are persistently undescended could indicate an impairment of LC renewal in cryptorchidism.

Cytotype Regulation Facilitates Repression of Hybrid Dysgenesis by Naturally Occurring KP Elements in Drosophila melanogaster

P elements inserted in the Telomere Associated Sequences (TAS) at the left end of the X chromosome are determiners of cytotype regulation of the entire P family of transposons. This regulation is mediated by Piwi-interacting (pi) RNAs derived from the telomeric P elements (TPs). Because these piRNAs are transmitted maternally, cytotype regulation is manifested as a maternal effect of the TPs. When a TP is combined with a transgenic P element inserted at another locus, this maternal effect is strengthened. However, when certain TPs are combined with transgenes that contain the small P element known as KP, stronger regulation arises from a zygotic effect of the KP element. This zygotic effect is observed with transgenic KP elements that are structurally intact, as well as with KP elements that are fused to an ancillary promoter from the hsp70 gene. Zygotic regulation by a KP element occurs only when a TP was present in the maternal germ line, and it is more pronounced when the TP was also present in the grand-maternal germ line. However, this regulation does not require zygotic expression of the TP These observations can be explained if maternally transmitted piRNAs from TPs enable a polypeptide encoded by KP elements to repress P element transposition in zygotes that contain a KP element. In nature, repression by the KP polypeptide may therefore be facilitated by cytotype-mediating piRNAs.

Inutero exposure to diisononyl phthalate caused testicular dysgenesis of rat fetal testis

Diisononyl phthalate (DINP) is a synthetic material that has been widely used as a substitute for other plasticizers prohibited due to reproductive toxicity in consumer products. Some phthalates have been associated with testicular dysgenesis syndrome in male fetus when female pregnant dams were exposed to them. The present study investigated effects of DINP on fetal Leydig cell function and testis development. Female pregnant Sprague Dawley rats received control vehicle (corn oil) or DINP (10, 100, 500, and 1000 mg/kg) by oral gavage from gestational day (GD) 12 to 21. At GD 21.5, testicular testosterone production, fetal Leydig cell numbers and distribution, testicular gene and protein expression levels were examined. DINP showed dose-dependent increase of fetal Leydig cell aggregation with the low observed adverse-effect level (LOAEL) of 10 mg/kg and multinucleated gonocyte with LOAEL of 100 mg/kg. At 10 mg/kg, DINP also significantly increased fetal Leydig cell size, but inhibited insulin-like 3 and 3β-hydroxysteroid dehydrogenase gene expression and protein levels. DINP inhibited testicular testosterone levels at 1000 mg/kg. The results indicate that in utero exposure to DINP affects the expression levels of some fetal Leydig cell steroidogenic genes, gonocyte multinucleation and Leydig cell aggregation.

[Congenital disorders of gonadal differentiation: clinico-morphological variants and surgical treatment]

The article presents the results of examination and surgical treatment of 25 patients with congenital disorders of gonadal differentiation. Survey plan included an assessment of the external genitalia, karyotyping and molecular analysis of Y-chromosome, determination of serum gonadotropins and testosterone levels, visualization of the gonads using ultrasound and laparoscopy methods, and intraoperative morphological examination of the material. Based on the results of a comprehensive survey, mixed testicular dysgenesis was identified in 25% of patients, complete testicular dysgenesis--in 16%, partial gonadal dysgenesis--in 44%, ovotesticular violation of sexualization--in 16% of patients. Clinical, macroscopic and morphological characteristics of each of these options are defined. The choice of sexual identity and tactics of surgical treatment are explained.

Regional differences and temporal trends in male reproductive health disorders: semen quality may be a sensitive marker of environmental exposures

The decline in semen quality has been the subject of an animated debate. A recent prospective study now irrefutably shows a decline in semen quality in men from Finland, a country that previously boasted good semen quality. Semen quality has, in some countries, reached a level where a considerable fraction of young men are at risk of fertility problems. Impaired semen quality, testicular cancer, cryptorchidism and hypospadias are risk factors for each other, and the testicular dysgenesis syndrome (TDS) has been put forward to explain the observations. This syndrome implies that the four disease entities share the same patho-physiological etiology caused by disturbed testicular development in early fetal life. It seems likely that the rapid rise in TDS-associated conditions can, at least partly, be explained by environmental factors. Animal studies provide strong evidence that manmade chemicals can disrupt the hormone dependent pathways responsible for fetal gonadal development, subsequently leading to TDS-like symptoms. In humans, fetal exposure to endocrine disrupting substances may play a role, although genetic factors are probably also involved. Recent studies indicate that exposure to endocrine disrupters also in adulthood may affect semen quality and reproductive hormones. Causal relationships are inherently difficult to establish in humans, and a clear connection between the disorders and specific toxicants has not been established. It seems likely that the cumulative effects of various low-dose exposures to endocrine disrupters in our environment are responsible for the adverse effects in the male reproductive system. Semen quality may be the most sensitive marker of adverse environmental exposures, and we suggest that standardized surveillance studies of semen quality are continued or initiated to monitor the combined effects of various preventive actions.

Splenogonadal fusion and sex reversal

Splenogonadal fusion is a rare congenital malformation where an abnormal union occurs between the spleen and gonad or mesonephric derivatives. Although it occurs in females it is much less prevalent than in males (male:female ratio, 16:1), but this may partly be because of the inaccessibility of the female gonads leading to under-diagnosis. To our knowledge this is the first case of splenogonadal fusion associated with sex reversal reported in the literature.

Correlation of intercentromeric distance, mosaicism, and sexual phenotype: molecular localization of breakpoints in isodicentric Y chromosomes

Isodicentric chromosomes are among the structural abnormalities of the Y chromosome that are commonly identified in patients. The simultaneous 45,X cell line that is generated in cell division due to instability of the isodicentric Y chromosome [idic(Y)] has long been hypothesized to explain the variable sexual development of these patients, although gonads have been studied in only a subset of cases. We report here on the molecular localization of breakpoints in ten patients with an idic(Y). Breakpoints were mapped by FISH using BACs; gonads and fibroblasts were also analyzed when possible to evaluate the level of mosaicism. First, we demonstrate great tissue variability in the distribution of idic(Y). Second, palindromes and direct repeats were near the breakpoint of several idic(Y), suggesting that these sequences play a role in the formation of idic(Y). Finally, our data suggest that intercentromeric distance has a negative influence on the stability of idic(Y), as a greater proportion of cells with breakage or loss of the idic(Y) were found in idic(Y) with a greater intercentromeric distance. Females had a significantly greater intercentromeric distance on their idic(Y) than did males. In conclusion, our study indicates that the Y chromosome contains sequences that are more prone to formation of isodicentric chromosomes. We also demonstrate that patients with an intercentromeric distance greater than 20 Mb on their idic(Y) are at increased risk of having a female sexual phenotype.

Organochlorine compounds and testicular dysgenesis syndrome: human data

Cryptorchidism, hypospadias, subfertility and testicular germ-cell tumour have been suggested to comprise a testicular dysgenesis syndrome (TDS) based on the premise that each may derive from perturbations of embryonal programming and gonadal development during foetal life. Endocrine-disrupting chemicals have been hypothesized to be associated with these disorders, given the importance of sex steroid hormones in urogenital development and homeostasis. Organochlorines are one such set of compounds which are defined as containing between one and ten covalently bonded chlorine atoms. These compounds are persistent pollutants with long half-lives, accumulate in adipose tissue when ingested, bioaccumulate and biomagnify, and have complex and variable toxicological profiles. Examples of organochlorines include dichloro-diphenyl-trichloroethane and its metabolites, polychlorinated biphenyls, and chlordane. In this comprehensive review of human epidemiologic studies which have tested for associations between organochlorines and facets of TDS, we find evidence for associations between the exposures p,p'-DDE, cis-nonachlor and trans-nonachlor with testicular germ-cell tumour. The sum of the evidence from human epidemiological studies does not indicate any association between specific organochlorines studied and cryptorchidism, hypospadias or fertility. Many other endocrine-disrupting chemicals, including additional organochlorines, have yet to be assessed in relation to disorders associated with TDS, yet study of such chemicals has strong scientific merit given the relevance of such hypotheses to urogenital development.

Gonadal tumours and DSD

Disorders of sex development (DSD), previously referred to as intersex, has been recognised as one of the main risk factors for development of type II germ cell tumours (GCTs), that is, seminomas/dysgerminomas and non-seminomas (e.g., embryonal carcinoma, yolk sac tumour, choriocarcinoma and teratoma). Within the testis, this type of cancer is the most frequent malignancy in adolescent and young adult Caucasian males. Although these males are not known to have dysgenetic gonads, the similarities in the resulting tumours suggest a common aetiological mechanism(s),--genetically, environmentally or a combination of both. Within the group of DSD patients, being in fact congenital conditions, the risk of malignant transformation of germ cells is highly heterogeneous, depending on a number of parameters, some of which have only recently been identified. Understanding of these recent insights will stimulate further research, with the final aim to develop an informative clinical decision tree for DSD patients, which includes optimal (early) diagnosis without overtreatment, such as prophylactic gonadectomy in the case of a low tumour risk.

Mixed gonadal dysgenesis in a 45,X neonate with chromosome Y material in the dysgenetic gonad

We report on a neonate with a disorder of sex development, Prader 3-4 external genitalia and a palpable structure in the right inguinal canal suggestive of gonadal tissue. Chromosome studies on blood lymphocytes showed monosomy of chromosome X. Laparoscopy identified a streak-like gonad on the left side, unicorn uterus and a dysgenetic testis on the right, attached to a Fallopian tube. Because of the unilateral palpable gonad and the presence of ambiguous genitalia we investigated further for the presence of Y material. Quantitative fluorescent PCR analysis of material from the dysgenetic gonad and skin fibroblasts revealed the presence of chromosome Y-derived sequences, suggesting sex chromosome mosaicism. In 45,X/46,XY mosaicism, chromosome studies carried out on peripheral lymphocytes do not always reflect the proportion of cell lines in the gonads. The detection of Y chromosome material in a dysgenetic gonad is extremely significant, due to the high risk of malignant transformation.

Cryptorchidism as part of the testicular dysgenesis syndrome: the environmental connection

Cryptorchidism is part of the testicular dysgenesis syndrome (TDS), which includes other male reproductive disorders such as hypospadias, testis cancer and reduced semen quality. These diseases appear to be linked by common pathogenic mechanisms, interfering with normal fetal testis development. Testis development and descent is dependent on androgens and thus on an intact hypothalamus-pituitary-gonadal axis. Although cryptorchidism occurs in rare syndromes and genetic disorders, in the majority of children the etiology remains open. Many maternal and fetal risk factors have been previously identified but recently, scientific focus has also been directed to environmental hormone disrupting chemicals and lifestyle, as the prevalence of testis cancer and cryptorchidism has increased and semen quality decreased over few decades in several countries. Some persistent environmental chemicals, e.g. polychlorinated pesticides and polybrominated flame retardants, were associated with testicular maldescent and testis cancer. In addition, prenatal exposure to phthalates was negatively correlated to testosterone levels and anogenital distance as a measure of androgen effect in infant boys. Alcohol consumption and maternal smoking during pregnancy also appeared to be a risk factor for cryptorchidism. Thus, current evidence suggests that the development of the male reproductive tract may be susceptible to adverse effects of environmental hormone disrupters.

[Molecular and cytogenetic study on 5 cases with gonadal dysgenesis: clinical applications of fluorescence in situ hybridization(FISH) and BAC-FISH]

OBJECTIVE

To explore the applications of fluorescence in situ hybridization (FISH) in the diagnosis for the patients with gonadal dysgenesis.

METHODS

After routine gynecologic examination, ultrasonography and endocrine examination, 5 cases of gonadal dysgenesis and hypogonadism were analyzed by using chromosomal diagnoses including G-banding, Q-banding, multiplex FISH and BAC-FISH analyses.

RESULTS

Among the 5 cases of gonad agenesis patients, 2 were pure gonadal dysgenesis with 46, XY karyotype, 3 were mixed gonadal dysgenesis with mos 45, X/47, XXX; 45, X/46, XY or 46, X, der(Y) karyotype.

CONCLUSION

Sex chromosomal abnormalities resulted in gonadal dysgenesis symptoms. Applications of FISH and BAC-FISH analyses can correctly diagnose the sex chromosomal abnormalities for patients with gonad agenesis and provide accurate medical genetic data for clinical diagnosis and therapy.

Comparison of bone mineral density and body proportions between women with complete androgen insensitivity syndrome and women with gonadal dysgenesis

OBJECTIVES

To compare bone mineral density (BMD) and body proportions between women with complete androgen insensitivity syndrome (CAIS) and with gonadal dysgenesis (GD).

SETTING

Adult Disorders of Sexual Development and Ovarian Failure Clinics at University College London Hospitals.

DESIGN

Retrospective cross-sectional study of three groups of women aged 17-58 years with varying degrees of exposure to sex hormones and different combinations of sex chromosomes. Forty-six subjects had CAIS, 18 had GD and 46,XY (GD(XY)), and 25 had GD and 46,XX (GD(XX)). In addition, body proportions of subgroups of these women were analysed.

OUTCOME MEASURES

Oestrogen therapy, karyotype, anthropometry and BMD.

RESULTS

Height differed between groups (F ratio 5.2, P=0.007)), with GD(XX) women being the shortest (mean+/-s.d.: 1.66+/-0.10 m), GD(XY) women the tallest (1.74+/-0.09 m) and CAIS women were in-between (1.70+/-0.07 m). Delayed gonadectomy resulted in taller stature in CAIS women (P=0.011). The ratio of lower to upper body length in GD(XY) women was significantly (P=0.001) greater than that of CAIS women. Multivariate logistic regression analysis (adjusted for age and height) showed that among women with XY karyotype, GD(XY) women were 5.2 times (95% confidence interval (CI): 1.3-20.1, P=0.018) more likely than CAIS women to have a low hip BMD. This difference was not evident among women with GD of different karyotypes (P=0.938). Spinal BMD did not differ between subject groups. Further adjustment for oestrogen replacement did not alter these relationships.

CONCLUSIONS

Taller stature in late gonadectomised CAIS women suggests an oestrogen deficiency in these women prior to gonadectomy. Increased lower to upper body ratio in GD(XY) women compared with the other groups implies that these subjects have the greatest degree of oestrogen deficiency in puberty. Androgen rather than sex chromosomes may play an important role in cortical bone mineralisation in CAIS women, probably via estrogen receptor-alpha either directly or via aromatisation during critical periods of growth prior to gonadectomy.

Tumor risk in disorders of sex development (DSD)

Disorders of sex development (DSD), previously referred to as intersex disorders, comprise a variety of anomalies defined by congenital conditions in which chromosomal, gonadal, or anatomical sex is atypical. Besides issues such as gender assignment, clinical and diagnostic evaluation, surgical and psychosocial management, and sex steroid replacement, the significantly increased risk for developing specific types of malignancies is both clinically and biologically relevant. This relates to germ-cell tumors specifically in DSD patients with hypovirilization or gonadal dysgenesis. The presence of a well-defined part of the Y chromosome (known as the GBY region) is a prerequisite for malignant transformation, for which the testis-specific protein on the Y chromosome (TSPY) is a likely candidate gene. The precursor lesions of these cancers are carcinoma in situ (CIS)/intratubular germ-cell neoplasia unclassified (ITGCNU) in testicular tissue and gonadoblastoma in those without obvious testicular differentiation. Most recently, undifferentiated gonadal tissue (UGT) has been identified as the likely precursor for gonadoblastoma. The availability of markers for the different developmental stages of germ cells allows detailed investigation of the characteristics of normal and (pre)malignant germ cells. Although informative in a diagnostic setting for adult male patients, these markers - such as OCT3/4 - cannot easily distinguish (pre)malignant germ cells from germ cells showing delayed maturation. This latter phenomenon is frequently found in gonads of DSD patients, and may be related to the risk of malignant transformation. Thus, the mere application of these markers might result in over-diagnosis and unnecessary gonadectomy. It is proposed that morphological and histological evaluation of gonadal tissue, in combination with OCT3/4 and TSPY double immunohistochemistry and clinical parameters, is most informative in estimating the risk for germ-cell tumor development in the individual patient, and might in future be used to develop a decision tree for optimal management of patients with DSD.

Impact of the Y-containing cell line on histological differentiation patterns in dysgenetic gonads

OBJECTIVE

Gonadal karyotyping is considered a tool for increasing our knowledge of disturbed gonadal development in patients with gonadal dysgenesis and for estimating more accurately the risk for gonadoblastoma formation. The objective was to gain insight into the role of Y chromosome distribution in the histological heterogeneity of gonads of patients with gonadal dysgenesis.

DESIGN

Investigation of the possible relationship between peripheral blood karyotype, gonadal karyotype, morphological differentiation patterns of dysgenetic gonads and tumour formation.

PATIENTS

In total 22 gonadal samples from 19 patients with gonadal dysgenesis (45,X/46,XY and variants n = 14; 46,XY: n = 3; 46,XX: n = 2) were examined.

MEASUREMENTS

Morphological examination and immunohistochemical staining for testis specific protein, Y encoded (TSPY) and fluorescent and nonfluorescent in situ hybridization directly on gonadal tissue.

RESULTS

No correlation was observed between peripheral blood karyotype and gonadal karyotype or between gonadal karyotype and the corresponding differentiation pattern. A Y-containing cell line in Sertoli cells was encountered no more frequently than were other cell types.

CONCLUSIONS

The distribution of the Y-containing cell line in peripheral blood is not a suitable indicator for predicting the histological differentiation pattern found in the gonads of patients with gonadal dysgenesis. The analysis of Y-containing cell lines in the gonads of such patients could be informative with regard to the specific characteristics of gonadal development in humans as compared to chimeric mouse models. Moreover, it is essential to understand the mechanisms underlying disturbed gonadogenesis in these patients. As the gonadal karyotype is not related to the encountered gonadal differentiation pattern, it does not allow prediction of the risk for gonadoblastoma formation.

Role of androgens in fetal testis development and dysgenesis

This study sought to establish whether reduced androgen levels/action in the fetal rat testis induced by di(n-butyl) phthalate (DBP) contributes to dysgenetic features, namely reduced Sertoli cell number, occurrence of multinucleated gonocytes (MNG), and Leydig cell aggregation. Pregnant rats were administered treatments or cotreatments designed to manipulate testosterone levels [DBP, testosterone propionate (TP)] or action [flutamide, 7,12-dimethyl-benz[a]anthracene (DMBA)]. The aforementioned end points were analyzed and related to intratesticular testosterone (ITT) levels and peripheral androgen action (anogenital distance). Dysgenetic features were also evaluated in mice with inactivation of the androgen receptor (testicular feminized or ARKO mice). Exposure to DBP alone, or combined with flutamide, DMBA, or TP, resulted in reduced Sertoli cell number and ITT levels, as did exposure to TP alone; coadministration of DBP + TP caused the most severe reduction in both parameters. A positive correlation between ITT levels and Sertoli cell number was found (r = 0.791; P = 0.019). Similarly, exposure to DBP alone, or as a cotreatment, significantly increased occurrence of MNG and Leydig cell aggregation, and these were negatively correlated with ITT levels. Exposure to flutamide or DMBA alone had no significant effect on these dysgenetic end points. These findings suggest that reduced ITT decreases fetal Sertoli cell numbers and might be involved in Leydig cell aggregation and MNG. However, of these three end points, only Sertoli cell number was affected significantly in ARKO/testicular feminized mice with absent androgen action. Therefore, induction of MNG and Leydig cell aggregation might result from DBP-induced effects other than suppression of ITT levels.

[Pathogenesis of neoplastic changes in germ cells as a developmental aspect]

Fetal germ cells transform neoplastically probably at the fetal period of life. The best place for their maintenance is a testis with the disturbed organogenesis (differentiation). These testes are called dysgenetic gonads. Besides the classical form of gonadal dysgenesis, appearing by the reversed sex features (female in genetic males), there are probably hidden forms without the disturbances in the sex differentiation. The overt and hidden disturbances of the testes' organogenesis are called testicular dysgenesis syndrome (TDS). Gonadal dysgenesis is more frequent in normal male karyotype than in numerical and structural aberrations of sex chromosomes. The cause of TDS is an inappropriate expression of genes of Y chromosome or autosomes, taking part in testicular differentiation, and/or exposition to the influence of environmental factors, mainly with estrogen-like action. It is supposed that TDS determines a cascade of events leading to germ cell tumours (GCT). This mechanism may appear as follows: 1) the inhibited organogenesis of seminal tubules (sometimes at the level of sex cords) causes 2) the delay in differentiation and development of germ and somatic Sertoli/granulosa cells; 3) disturbed somatic cells contribute to the death of most germ cells, but germ cells which retain fetal antigens have the possibility to survive and proliferate; 4) if the survived germ cells are in the undifferentiated tissue of fetal gonad (retardation of testicular development at the level of gonadal anlage) their clonal expansion leads to the creation of neoplastic lesion termed gonadoblastoma. With time gonadoblastoma undergoes atrophy and/or calcification or may transform into GCT; 5) if the survived germ cells are placed inside the seminal tubules, they have better conditions to persist in the unchanged, but developmentally delayed, form for many years as preinvasive carcinoma in situ (CIS). CIS cells can disappear but with the advancing puberty they may give rise to GCT under the influence of gonadotropins and androgens.

Intratubular germ cell neoplasia of unclassified type

Intratubular germ cell neoplasia of unclassified type (IGCNU) is the precursor lesion of adult testicular germ cell invasive tumors. Primordial germ cells (PGCs) are recognized as the cells of origin of testicular germ cell tumors (TGCTs) because of the genetic and phenotypic characteristics analyzed. The most important risk factors responsible for abnormal development of PGCs are environmental, including the testicular dysgenetic syndromes that generate a better microenvironmentfor survival of IGCNU cells, an abnormal relationship with Sertoli cells, and an abnormal hormonal exposure at the time of testicular differentiation in utero. Furthermore, a familial TGCT susceptibility gene (TGCT1), localized at Xq27, is associated with a higher risk for bilateral tumors and possibly cryptorchidism. The normal tetraploid pattern and the consequent genomic instability of germinal cell DNA are considered sufficient per se for neoplastic transformation. The altered expression of oncogenes and suppressor genes due to nonrandom chromosomal numerical aberrations are involved in the development of IGCNU. Some of these genes are considered responsible for bilaterality, while other genes characterize the similarity between IGCNU cells and PGCs or are involved in the neoplastic transformation, histotype differentiation, and invasivity. In spite of the monomorphic seminomatous appearance of cells in IGCNU, it is becoming increasingly evident that they hide an intrinsic heterogeneity capable of committing neoplastic cells to an embryonal and pluripotent development associated or not with a seminomatous phenotype.

Gonadoblastoma arising in undifferentiated gonadal tissue within dysgenetic gonads

PURPOSE

The purpose of the study was to define the histological origin of gonadoblastomas, allowing the identification of high-risk patients.

EXPERIMENTAL DESIGN

Sixty paraffin-embedded gonadectomy or gonadal biopsy samples of 43 patients with gonadal dysgenesis were selected from our archives. We studied the morphology and immunohistochemical properties of the germ cells in 40 samples without neoplastic transformation and compared these findings with the morphological and immunohistochemical characteristics of 20 samples containing gonadoblastoma/dysgerminoma.

RESULTS

The overall incidence of germ cell tumors in our patient series was 35%. In dysgenetic gonads without germ cell neoplasia, besides the presence of areas with testicular and/or ovarian differentiation, areas of undifferentiated gonadal tissue were identified in 13 of 40 samples (32.5%). A subpopulation of germ cells within these undifferentiated areas stained positive for octamer binding transcription factor (OCT)3/4, the stem cell factor receptor, placental-like alkaline phosphatase, and testis-specific protein-Y encoded. Gonadoblastoma germ cells display identical staining results. Moreover, in gonads containing gonadoblastoma, adjacent to this lesion, areas of undifferentiated gonadal tissue with identical immunohistochemical characteristics were identified in 10 of 20 samples (50%). No adjacent tissue was available in five cases, whereas in the five remaining cases, it consisted of streak tissue. In three cases, an accumulation of OCT3/4-positive germ cells in the proximity of the malignant lesions was found, suggesting clonal expansion and final organization into gonadoblastoma nests.

CONCLUSIONS

Based on these observations, we hypothesize that gonadoblastomas originate from surviving OCT3/4-positive germ cells in areas of undifferentiated gonadal tissue within the dysgenetic gonad. Supportive evidence was obtained that carcinoma in situ arises in regions with testicular differentiation.

Insulin-like factor 3 gene mutations in testicular dysgenesis syndrome: clinical and functional characterization

Insulin-like factor 3 (INSL3) plays a crucial role in testicular descent. Genetic ablation of Insl3 or its G protein-coupled receptor, leucine-rich repeat-containing G-protein-coupled receptor (Lgr8), causes cryptorchidism in mice. Mutation analyses of INSL3 in humans showed an association with cryptorchidism but led to non-conclusive data about a causative role. In this study, we explored the hypothesis that mutations in INSL3 may be associated with the signs of testicular dysgenesis syndrome (TDS). We screened for mutations in INSL3 gene in 967 subjects with a history of maldescended testes and/or infertility and/or testicular cancer and in 450 controls. Furthermore, we carried out in vitro functional analysis of three novel mutations by analysis of INSL3-dependent cAMP increase in cells expressing LGR8. We found six INSL3 mutations in 18 of 967 patients (1.9%) and no mutations in controls. Prevalence of mutations was similar in the different groups of patients (cryptorchidism and/or infertility and/testicular cancer). Three mutations were novel findings (R4H, W69R, and R72K); however, their analysis showed normal cAMP increase after the activation of LGR8 receptor. In conclusion, we found a significant association of INSL3 gene mutations in men presenting one or more signs of TDS syndrome. However, a causative role for some of these mutations is not clearly supported by functional analyses. Although a role for mutations of INSL3 and LGR8 genes in cryptorchidism is reasonable, additional studies are needed to establish an association between the disruption of INSL3 pathway and higher risk of infertility or testicular cancer.

Primary amenorrhea associated with ovarian leiomyoma in a baboon (Papio hamadryas)

A 6-y-old female baboon was examined due to absence of menstrual cycling and secondary sex characteristics and failure to reproduce. The mammary glands and vaginal introitus were hypoplastic, the clitoris was prominent, and the perineal skin was immature with lack of cyclic color alterations and sexual swelling. Evaluation of the reproductive tract revealed a hypoplastic uterus and rudimentary ovaries with the presence of an ovarian leiomyoma within the right ovary. Hormonal values (estradiol, progesterone) were low and comparable to those of adult males or ovariectomized females. Adrenal and pituitary hormones (dehydroepiandrosterone, luteinizing and follicular stimulating hormones) and pituitary structure were within normal limits for this species. The baboon had a normal 42,XX karyotype. These findings suggest primary amenorrhea due to ovarian dysgenesis. This is the first report of a case of primary amenorrhea due to ovarian dysgenesis with a normal karyotype associated with a unilateral ovarian leiomyoma in the baboon. Continued studies of noncycling female nonhuman primates in captive breeding colonies may lead to a greater understanding of the underlying causes of this condition.

Reproductive dysgenesis in wildlife: a comparative view

Abnormal reproductive development in males has been linked to environmental contaminant exposure in a wide variety of vertebrates. These include humans, rodent models, and a large number of comparative wildlife species. In human males, abnormal reproductive development can manifest as a suite of symptoms, described collectively as testicular dysgenesis syndrome (TDS). TDS is also described as demasculinization or feminization of the male phenotype. The suite includes cryptorchidism, in situ germ cell carcinoma of the testis and overt testicular cancer, reduced semen quality, and hypospadias. In this paper, we review examples of TDS among comparative species. Wildlife exposed to environmental contaminants are susceptible to some of the same developmental abnormalities and subsequent symptoms as those seen in human males with TDS. There are additional end points, which are also discussed. In some cases, the symptoms are more severe than those normally seen in humans with TDS (i.e. oocytes developing within the testis) because some non-mammalian species exhibit greater innate reproductive plasticity, and are thus more easily feminized. Based on our review, we present an approach regarding the ontogeny of TDS. Namely, we suggest that male susceptibility to the androgynizing influences of environmental contaminants originates in the sexually undifferentiated embryo, which, in almost all species, including humans, consists of bipotential reproductive tissues. These tissues can develop as either male or female and their ultimate direction depends on the environment in which they develop.

Mitotic activity of Sertoli cells in adult human testis: an immunohistochemical study to characterize Sertoli cells in testicular cords from patients showing testicular dysgenesis syndrome

During puberty, normal somatic Sertoli cells undergo dramatic morphological changes due to the differentiation of immature pre-Sertoli cells in functionally active adult Sertoli cells. Sertoli cell maturation is accompanied with loss of their mitotic activity before onset of spermatogenesis and loss of pre-pubertal and occurrence of adult immunohistochemical Sertoli cell differentiation markers. Testes of infertile adult patients often exhibit numerous histological signs of testicular dysgenesis syndrome (TDS) such as microliths, Sertoli cell only (SCO) tubules, tubules containing carcinoma in situ and immature seminiferous tubules (Sertoli cell nodules). Sertoli cell tumours, however, are very rare neoplasms possibly due to the fact that the mechanism and temporal origin of neoplastic Sertoli cells underlying Sertoli cell tumourigenesis still remain unknown. To clarify the state of Sertoli cell differentiation in both immature seminiferous tubules of adult patients with TDS and Sertoli cell tumour, we compared the expression of the Sertoli cell differentiation markers vimentin, inhibin-alpha, anti-Muellerian-hormone, cytokeratin 18, M2A-antigen, androgen receptor and connexin43 with that of SCO tubules with hyperplasia. In addition, we demonstrated for the first time the existence of proliferating Sertoli cells by Ki67- and PCNA-immunostaining in Sertoli cell nodules of the adult human testis. Our data indicate that mitotically active Sertoli cells in Sertoli cell nodules will be arrested prior to puberty and, contrary to dogma, do not represent foetal or neonatal cells. Since all markers in Sertoli cell nodules revealed a staining pattern identical to that in neoplastic Sertoli cells, but different to that in Sertoli cells of SCO tubules with hyperplasia, it may be speculated that Sertoli cell tumours in adult men may originate from Sertoli cell nodules.

Genetic investigation of the TSPYL1 gene in sudden infant death syndrome

BACKGROUND

Sudden infant death syndrome (SIDS) constitutes the most frequent cause of death in the postperinatal period in Germany. Recently, a lethal phenotype characterized by sudden infant death with dysgenesis of the testes syndrome (SIDDT) was identified to be caused by loss of function mutations in the TSPYL1 gene.

PURPOSE

The study's purpose was to reveal a possible role of TSPYL1 in SIDS.

METHODS

DNA samples of 126 SIDS cases and 261 controls were investigated.

RESULTS

We found five sequence variations, each of them causing an amino acid substitution. No Hardy Weinberg disequilibrium and no significant difference in allele frequencies between patients and controls were observed for any variation. In one female patient a p.F366L amino acid polymorphism was found heterozygous, which could not be displayed in controls. A pathogenic implication of this substitution, which is conserved in primates and rodents, cannot be ruled out completely. Because SIDDT is the result of homozygous TSPYL1 mutations, this heterozygous exchange cannot solely explain the sudden death in this child. The reported mutation associated with SIDDT (457_458insG) was not detectable in our cohort.

CONCLUSION

No association of sequence variations in the TSPYL1 gene and SIDS has been found in a German cohort. Genetic analysis of TSPYL1 seems to be of limited significance in the differential diagnosis of SIDS without dysgenesis of the testes.

Gonadoblastoma: evidence for a stepwise progression to dysgerminoma in a dysgenetic ovary

Gonadoblastomas are neoplasms of dysgenetic gonads which may undergo regression or become overgrown by malignant germ cell tumors (mGCTs). Since little is known about their relationship to normal gonadal development and mGCTs, we studied the phenotype and antigenic profile of gonadoblastomas in comparison with adjacent dysgerminomas and fetal gonads. Three cases of gonadoblastomas and fetal gonads of both sexes were analyzed using oncofetal markers to M2A-antigen (M2A), germ cell alkaline phosphatase (PLAP/GCAP), receptor tyrosine kinase c-kit (c-kit), and somatic angiotensin converting enzyme (sACE) as well as the proliferation marker MIB-1. Morphologically, microfollicular pattern of gonadoblastomas showed a fetal germ cell organization reminiscent of oocytic clusters of fetal ovaries. They contained both cell types, similar to oocytes (M2A-, GCAP-, c-kit+/-, sACE-) and oogonia (M2A+, GCAP+, c-kit+, sACE+). The percentage of germ cells immunoreactive for oncofetal markers and the proliferation index increased from microfollicular over coronary patterns to adjacent dysgerminomas. Supportive cells of gonadoblastomas showed a uniform phenotype (CK18+, vimentin+, sACE+, alpha-inhibin+, M2A-) but in contrast to fetal germ cells lacked a clear equivalence to fetal tissues. Our results show that gonadoblastomas mimic female fetal ovary and exhibit a stepwise progression from follicular pattern to coronary pattern and finally to dysgerminomas.

A 46,X,inv(Y) young woman with gonadal dysgenesis and gonadoblastoma: Cytogenetics, molecular, and methylation studies

Cytogenetic analysis of a young woman with gonadal dysgenesis and bilateral gonadoblastoma shared a male karyotype with a rearranged Y chromosome, interpreted as a pericentric inversion. The breakpoints, defined by fluorescent in situ hybridization (FISH), were located on the very distal short arm on band Yp11.31 and in the middle of the Yq12 long arm heterochromatic region. FISH analysis documented that the short arm breakpoint was 93 Kb distal to SRY and disrupted the CD99 gene, which was transposed to the distal portion of Yq12. The proposita's phenotype was similar to that of XY individuals with gonadal dysgenesis but without signs of Ullrich-Turner syndrome. There were no mutations in the SRY gene. Cytogenetic analysis in the proposita's father showed mosaicism of a normal Y chromosome and several different rearrangements, such as deletion of a heterochromatin portion at band Yq12.2, a fragile site at the same band, structural rearrangements between the Y-chromosome and other autosomes, Y-chromosome aneuploidies, and "Premature Centromere Division" (PCD) anomaly. The proposita's inverted Y chromosome appears to have originated from paternal Y chromosome instability. The patient's female phenotype could be due to SRY CpG methylation-mediated positional effects (PEV).

Transcription Factor AP-2γ Is a Developmentally Regulated Marker of Testicular CarcinomaIn situand Germ Cell Tumors

PURPOSE

Transcription factor activator protein-2gamma (TFAP2C, AP-2gamma) was reported previously in extraembryonic ectoderm and breast carcinomas but not in the testis. In our recent gene expression study we detected AP-2gamma in carcinoma in situ testis (CIS, or intratubular germ cell neoplasia), precursor of testicular germ cell tumors. In this study we aimed to investigate the expression pattern of AP-2gamma and to shed light on this factor in germ cell differentiation and the pathogenesis of germ cell neoplasia.

EXPERIMENTAL DESIGN

We analyzed expression pattern of AP-2gamma at the RNA and protein level in normal human tissues and a panel of tumors and tumor-derived cell lines. In the gonads, we established the ontogeny of expression of AP-2gamma in normal and dysgenetic samples. We also investigated the regulation of AP-2gamma by steroids and retinoic acid.

RESULTS

We detected abundant AP-2gamma in testicular CIS and in testicular germ cell tumors of young adults and confirmed differential expression of AP-2gamma in somatic tumors. We found that AP-2gamma expression was regulated by retinoic acid in an embryonal carcinoma cell line (NT2). The investigation of ontogeny of AP-2gamma protein expression in fetal gonads revealed that it was confined to oogonia/gonocytes and was down-regulated with germ cell differentiation. In some prepubertal intersex cases, AP-2gamma was detected outside of the normal window of expression, probably marking neoplastic transformation of germ cells.

CONCLUSIONS

AP-2gamma is developmentally regulated and associated with the undifferentiated phenotype in germ cells. This transcription factor may be involved in self-renewal and survival of immature germ cells and tissue-specific stem cells. AP-2gamma is a novel marker of testicular CIS and CIS-derived tumors.

Urogenital and caudal dysgenesis in adrenocortical dysplasia (acd) mice is caused by a splicing mutation in a novel telomeric regulator

Adrenocortical dysplasia (acd) is a spontaneous autosomal recessive mouse mutant with developmental defects in organs derived from the urogenital ridge. In surviving adult mutants, adrenocortical dysplasia and hypofunction are predominant features. Adults are infertile due to lack of mature germ cells, and 50% develop hydronephrosis due to ureteral hyperplasia. We report the identification of a splice donor mutation in a novel gene, which is the mouse ortholog of a newly discovered telomeric regulator. This gene (Acd) has recently been characterized as a novel component of the TRF1 protein complex that controls telomere elongation by telomerase. Characterization of Acd transcripts in mutant animals reveals two abnormal transcripts, consistent with a splicing defect. Expression of a wild-type Acd transgene in acd mutants rescues the observed phenotype. Most mutants die within 1-2 days of life on the original genetic background. Analysis of these mutant embryos reveals variable, yet striking defects in caudal specification, limb patterning and axial skeleton formation. In the tail bud, reduced expression of Wnt3a and Dll1 correlates with phenotypic severity of caudal regression. In the limbs, expression of Fgf8 is expanded in the dorsal-ventral axis of the apical ectodermal ridge and shortened in the anterior-posterior axis, consistent with the observed loss of anterior digits in older embryos. The axial skeleton of mutant embryos shows abnormal vertebral fusions in cervical, lumbar and caudal regions. This is the first report to show that a telomeric regulator is required for proper urogenital ridge differentiation, axial skeleton specification and limb patterning in mice.

Genomic heterogeneity and instability of the AZF locus on the human Y chromosome

The spermatogenesis locus azoospermia factor (AZF) in Yq11 has been mapped to three microdeletion intervals designated as AZFa, AZFb, and AZFc. They are caused by intrachromosomal recombination events between large homologous repetitive sequence blocks, and AZFc microdeletions are now recognised as the most frequent known genetic lesion causing male infertility. However, in the same Y-region, large genomic heterogeneities are also observed in fertile men, and only complete AZFa and AZFb deletions are associated with a specific testicular pathology. Partial AZF deletions are associated with variable pathologies and partial AZFc deletions may even have no impact on male fertility. This suggests a genetic redundancy of the multi-copy genes in AZFb and AZFc and a causative relationship between the occurrence of first microdeletions then macrodeletions in the repetitive structure of Yq11 where large palindromes are probably promoting multiple gene conversions and AZF rearrangements.

Gonadal mosaicism in severe Pallister-Hall syndrome

Pallister-Hall syndrome (PHS, MIM #146510) is characterized by central and postaxial polydactyly, hypothalamic hamartoma (HH), bifid epiglottis, imperforate anus, renal abnormalities, and pulmonary segmentation anomalies. It is inherited in an autosomal dominant pattern. Here, we describe a family with two affected children manifesting severe PHS with mental retardation, behavioral problems, and intractable seizures. Both parents are healthy, with normal intelligence, and have no malformations on physical, laryngoscopic, and cranial MRI exam. The atypical presentation of these children and the absence of parental manifestations suggested an autosomal recessive mode of inheritance or gonadal mosaicism. Sequencing of GLI3 revealed a two nucleotide deletion in exon 15 (c.3385_3386delTT) predicting a frameshift and premature stop at codon 1129 (p.F1129X) in the children while both parents have wild type alleles. Genotyping with GLI3 intragenic markers revealed that both children inherited the abnormal allele from their mother thus supporting gonadal mosaicism as the underlying mechanism of inheritance (paternity was confirmed). This is the first reported case of gonadal mosaicism in PHS. The severe CNS manifestations of these children are reminiscent of children with non-syndromic HH who often have progressive mental retardation with behavioral problems and intractable seizures. We conclude that the phenotypic spectrum of PHS can include severe CNS manifestations and that recurrence risks for PHS should include a proviso for gonadal mosaicism, though the frequency cannot be calculated from a single case report. Published 2003 Wiley-Liss, Inc.

An unusal case of hermaphroditism--a 46,XX/69,XXY chimera

A diploid/triploid karyotype is an uncommon but important cause of true hermaphroditism and ambiguous genitalia. Individuals have a recognisable phenotype and characteristic hydatidiform placental changes. We report a 46,XX/69,XXY chimeric hermaphrodite. This case highlights the typical features (large placenta, intrauterine growth retardation, asymmetric growth, cranio-facial anomalies, syndactyly and pigmentary dysplasia). It illustrates the importance of obtaining skin and gonadal karyotypes in the case of genital ambiguity, as the venous lymphocytic karyotype is usually diploid.

Do environmental factors play a role in the aetiology of carcinoma in situ testis and the testicular dysgenesis syndrome?

The hypothesis of the Testicular Dysgenesis Syndrome (TDS), first suggested in 2001, propose that several disorders of the male reproductive system such as infertility, hypospadias, cryptorchidism and testicular cancer are all symptoms of TDS, which is most likely initiated during early foetal development, and may be provoked by external factors such as endocrine disruptors in addition to genetic predisposition. Testicular germ cell tumours (TGCTs), considered the most severe symptom of TDS, have increased in incidence during the last 60 years, to become the most common malignancy in young Caucasian men aged 17-45 years. TGCTs of young men originate from carcinoma in situ (CIS) cells. In the last few years, progress has been made identifying candidate genes involved in the neoplastic development of CIS, which may elucidate the timing of the initiation of CIS, currently thought to originate in foetal life from primordial germ cells or early gonocytes. Histological dysgenetic features are frequently seen in testes affected with the TDS components testis cancer or cryptorchidism. A TDS-like phenotype can be induced in male rats by in utero exposure to high concentrations of dibutyl phthalate (DBP) suggesting that ubiquitously present environmental endocrine disruptors may play a role in the aetiology of human TDS. So far, no animal model has been able to mimick all the symptoms of TDS including TGCTs although CIS-like cells have been found in a spontaneous testicular neoplasm in a rabbit.

XY female marmoset (Callithrix jacchus)

A marmoset (Callithrix jacchus) with atypical external genitalia was phenotypically and genetically characterized. Testosterone concentration correlated with that of female marmosets. Externally, there was only one opening for the urethra. Internal genitalia were characteristic of those of female marmosets, and consisted of ovaries, with follicles in various developmental stages, and uterus. Microscopically, a normal vaginal structure was found. An XX/XY chimerism and high steroid hormone values are normally found in common marmosets. Genetic analysis was used for in vivo determination of sex. The Y-linked zinc finger protein gene (ZFY) last intron, and sex-determining region Y gene (SRY) exon were found by use of polymerase chain reaction and posterior sequencing analyses, indicating that this marmoset had Y-linked chromosome sequences. Normal SRY exons can, therefore, be associated with female internal sexual organs in marmosets; this may be the first XY female described in non-human primates.

Neoplastic potential of germ cells in relation to disturbances of gonadal organogenesis and changes in karyotype

The study consisted of 46 intersexual patients who underwent gonadectomy at the age of 3 months to 19 years because of gonadal dysgenesis (GD; 40 cases) or true hermaphroditism (bisexual gonads; 6 cases). In patients with GD, the incidence of the 46,XY karyotype was 67.5%, whereas the remaining patients exhibited numerical and structural aberrations of sex chromosomes (NSASs), and all patients with bisexual gonads revealed NSAS. Seminoma was diagnosed in 1 patient with the 46,XY karyotype and pure GD (streak gonads). Intratubular carcinoma in situ (CIS) appeared as an exclusive lesion in 61.5% of 13 patients with mixed GD, in 54% of 11 patients with partial GD (bilateral testes), in 16.7% of 6 patients with bisexual gonads, and in none of 13 patients with pure GD. CIS also appeared in tubules in the vicinity of sex cord-derived tumors (gonadoblastoma nests and unclassified mixed germ cell-sex cord-stromal tumor; MGCSCST) and within the tumors. In 3 patients, gonadoblastoma replaced the whole bilateral gonads and is referred to as gonadoblastoma-only GD. The incidence of neoplastic lesions (mostly bilateral) was 90.9% in patients with partial GD, 76.9% (mostly unilateral) in patients with mixed GD, 23.1% (unilateral) in patients with pure GD, and 16.7% (unilateral) in patients with bisexual gonads. Disregarding types of disturbances of gonadal organogenesis, the incidence of lesions was 71.4% in 28 patients with the 46,XY karyotype and 35.3% in 17 patients with NSAS. We conclude, first, that NSAS is not a prerequisite for the appearance of GD and GD is more frequently associated with the 46,XY karyotype. Second, the spectrum of germ cell neoplastic lesions in GD is wider than reported. Besides germ cell carcinoma, CIS, and gonadoblastoma nests, the spectrum also includes a tumor of gonadoblastoma-only in cases of GD and MGCSCST. Third, the incidence of neoplastic lesions is related more to the severity of the disturbances of gonadal organogenesis than it is to aberrations in sex chromosomes. Fourth, less disturbed testicular organogenesis predisposes these patients more toward germ cell neoplastic lesions, which suggests that the testicular environment of a dysgenetic gonad plays an important role in germ cell neoplasia initiation, maintenance, or both.

The role of Müllerian inhibiting substance in the evaluation of phenotypic female patients with mild degrees of virilization

Müllerian inhibiting substance (MIS) is a sexually dimorphic gonadal hormone with proven efficacy in the evaluation of boys with cryptorchidism and children with intersex conditions. We examined the role of MIS determination in the evaluation of 65 phenotypic females with mild virilization. Among the 28 subjects with MIS values elevated above the normal female range, all had abnormal gonadal tissue: ovotestes in 11, testes in 7, dysgenetic gonads in 7, and MIS-secreting ovarian tumors in 3. Among the 37 children with serum MIS in the normal female range, 19 had detectable MIS and 18 had unmeasurable MIS. In the former group with measurable but normal female MIS values, 16 subjects had ovaries, 1 had an ovotestis, and 1 had dysgenetic gonads containing testicular elements. Of 18 children with undetectable MIS values, 16 had ovaries and 2 had ovarian dysgenesis. In this study, elevation of serum MIS above the normal female range was consistently associated with the presence of testicular tissue or MIS- secreting tumors, mandating additional evaluation and surgical exploration. A value within the normal female range in a virilized patient did not exclude dysgenetic testicular tissue or ovotestis, whereas undetectable values were consistent with the absence of testicular tissue.

Lack of RBM expression as a marker for carcinoma in situ of prepubertal dysgenetic testis

Individuals with various intersex states who carry Y-chromosome material bear a high risk of developing testicular neoplasia. In order to gain more insight into the pathogenesis of this neoplasia, the current study evaluates the differentiation of the seminiferous epithelium in 46,XY dysgenetic male pseudohermaphroditism. Immunohistochemical evaluation was performed using the germ cell-specific RNA-binding motif (RBM) protein (encoded by the Y-chromosome) to identify normal germ cells, whereas placental alkaline phosphatase (PLAP) was used to detect neoplastic germ cells. Differentiation of somatic Sertoli cells was assessed using cytokeratin-18 (CK-18) and anti-Müllerian hormone (AMH) as markers for immature Sertoli cells. Specimens were taken from surgically removed dysgenetic gonads of five children (46XY karyotype). Intratubular germ cell neoplasia (carcinoma in situ [CIS] of the testis) was detected in all of them. Normal germ cells revealed immunoreactivity for RBM, whereas the PLAP-positive neoplastic germ cells were negative for RBM expression. Sertoli cells revealed an immature phenotype indicated by AMH expression in their cytoplasm. The design of the current study is unique in its assessment of the state of germ cell differentiation in dysgenetic gonads by the use of the RBM protein, which was expressed only in normal germ cells but not in those of CIS. Testicular dysgenesis interrupted the normal differentiation of the germ line and had no effect on the immature phenotype of the prepubertal Sertoli cells. This points toward the germinal component of CIS as the precursor for the promotion of testis cancer.