SRY alone can induce normal male sexual differentiation

46XX testicular disorder of sex development

In this case report, we present the case of a 31-year-old man who presented with primary infertility, azoospermia and occasional sexual dysfunction. History and general physical examination were unremarkable. Local examination showed bilateral low volume testes and remaining aspects of the male reproductive tract were unremarkable. Detailed investigation showed a hypergonadotropic hypogonadism suggestive of primary testicular failure. Genetic screening showed a 46XX karyotype and Y chromosome testing was positive for sex-determining region (SRY) gene. Ultrasound abdomen was normal renal system and adrenal glands. A diagnosis of 46XX testicular disorders of sex development (DSD) was made. The incidence of this disorder is estimated to be 1:20,000 males. Such syndromic male partners generally have normal external genitalia and discover this disorder only in adulthood because of infertility. Such men have small volume testes, azoospermia and hypergonadotropic hypogonadism. Genetic and endocrine consultations are necessary to manage hypergonadotropic hypogonadism. Testicular sperm extraction is not recommended as there are deletions in all regions of Y chromosome, and adoption or assisted reproduction technology with a sperm donor are fertility options.

46,XX Testicular Disorder of Sex Development (DSD): A Case Report and Systematic Review

Background and objectives: XX male syndrome is part of the disorders of sex development (DSD). The patients generally have normal external genitalia and discover their pathology in adulthood because of infertility. There are no guidelines regarding XX male syndrome, so the aim of our study was to evaluate the literature evidence in order to guide the physicians in the management of these type of patients. Materials and Methods: We performed a systematic review of the available literature in September 2018, using MEDLINE, Web of Science, Embase and Google Scholar database to search for all published studies regarding XX male syndrome according to PRISMA guidelines. The following search terms were used: “46 XX male”, “DSD”, “infertility”, “hypogonadism”. Results: After appropriate screening we selected 37 papers. Mean (SD) age was 33.14 (11.4) years. Hair distribution was normal in 29/39 patients (74.3%), gynecomastia was absent in 22/39 cases (56.4%), normal testes volume was reported in 0/14, penis size was normal in 26/32 cases (81.2%), pubic hair had a normal development in 6/7 patients (85.7%), normal erectile function was present in 27/30 cases (90%) and libido was preserved in 20/20 patients (100%). The data revealed the common presence of hypergonadotropic hypogonadism. All patients had a 46,XX karyotype. The sex-determining region Y (SRY) gene was detected in 51/57 cases. The position of the SRY was on the Xp in the 97% of the cases. Conclusions: An appropriate physical examination should include the evaluation of genitalia to detect cryptorchidism, hypospadias, penis size, and gynecomastia; it is important to use a validated questionnaire to evaluate erectile dysfunction, such as the International Index of Erectile Function (IIEF). Semen analysis is mandatory and so is the karyotype test. Abdominal ultrasound is useful in order to exclude residual Müllerian structures. Genetic and endocrine consultations are necessary to assess a possible hypergonadotropic hypogonadism. Testicular sperm extraction is not recommended, and adoption or in vitro fertilization with a sperm donor are fertility options.

Sexual dimorphism in brain transcriptomes of Amami spiny rats (Tokudaia osimensis): a rodent species where males lack the Y chromosome

Background

Brain sexual differentiation is sculpted by precise coordination of steroid hormones during development. Programming of several brain regions in males depends upon aromatase conversion of testosterone to estrogen. However, it is not clear the direct contribution that Y chromosome associated genes, especially sex-determining region Y (Sry), might exert on brain sexual differentiation in therian mammals. Two species of spiny rats: Amami spiny rat (Tokudaia osimensis) and Tokunoshima spiny rat (T. tokunoshimensis) lack a Y chromosome/Sry, and these individuals possess an XO chromosome system in both sexes. Both Tokudaia species are highly endangered. To assess the neural transcriptome profile in male and female Amami spiny rats, RNA was isolated from brain samples of adult male and female spiny rats that had died accidentally and used for RNAseq analyses.

Results

RNAseq analyses confirmed that several genes and individual transcripts were differentially expressed between males and females. In males, seminal vesicle secretory protein 5 (Svs5) and cytochrome P450 1B1 (Cyp1b1) genes were significantly elevated compared to females, whereas serine (or cysteine) peptidase inhibitor, clade A, member 3 N (Serpina3n) was upregulated in females. Many individual transcripts elevated in males included those encoding for zinc finger proteins, e.g. zinc finger protein X-linked (Zfx).

Conclusions

This method successfully identified several genes and transcripts that showed expression differences in the brain of adult male and female Amami spiny rat. The functional significance of these findings, especially differential expression of transcripts encoding zinc finger proteins, in this unusual rodent species remains to be determined.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5426-6) contains supplementary material, which is available to authorized users.

Clinical and molecular studies in four patients with SRY-positive 46,XX testicular disorders of sex development: implications for variable sex development and genomic rearrangements

We report four patients with SRY-positive 46,XX testicular disorders of sex development (46,XX-TDSD) (cases 1-4). Case 1 exhibited underdeveloped external genitalia with hypospadias, case 2 manifested micropenis and cases 3 and 4 showed normal external genitalia. The Xp;Yp translocations occurred between the X- and the Y-differential regions in case 1, between PRKX and inverted PRKY in case 2 and between the X-chromosomal short arm pseudoautosomal region and the Y-differential regions in cases 3 and 4. The distance of the Yp breakpoint from SRY was ~0.75 Mb in case 1, ~6.5 Mb in case 2, ~2.3 Mb in case 3 and ~72 kb in case 4. The Xp;Yp translocation occurred within an 87-bp homologous segment of PRKX and PRKY in case 2, and between non-homologous regions with addition of an 18-bp sequence of unknown origin in case 4. X-inactivation analysis revealed random inactivation in cases 1-4. The results argue against the notion that undermasculinization in 46,XX-TDSD is prone to occur when translocated Yp materials are small (<100 kb of the Y-differential region), and imply that the Xp;Yp translocations result from several mechanisms including non-allelic homologous recombination and non-homologous end joining.

46,XX male disorder of sexual development:a case report

The main factor influencing sex determination of an embryo is the sex-determining region Y (SRY), a master regulatory gene located on the Y chromosome. The presence of SRY causes the bipotential gonad to differentiate into a testis. However, some individuals carry a Y chromosome but are phenotypically female (46,XY females) or have a female karyotype but are phenotypically male (46,XX males). 46, XX male is rare (1:20 000 in newborn males), and SRY positivity is responsible for this condition in approximately 90% of these subjects. External genitalia of 46,XX SRY-positive males appear as normal male external genitalia, and such cases are diagnosed when they present with small testes and/or infertility after puberty. Herein, we report an adolescent who presented with low testicular volume and who was diagnosed as a 46,XX male. SRY positivity was demonstrated in the patient by fluorescence in situ hybridization method.

46,XX sex reversal

In humans, sexual differentiation is directed by SRY, a master regulatory gene located at the Y chromosome. This gene initiates the male pathway or represses the female pathway by regulating the transcription of downstream genes; however, the precise mechanisms by which SRY acts are largely unknown. Moreover, several genes have recently been implicated in the development of the bipotential gonad even before SRY is expressed. In some individuals, the normal process of sexual differentiation is altered and a sex reversal disorder is observed. These subjects present the chromosomes of one sex but the physical attributes of the other. Over the past years, considerable progress has been achieved in the molecular characterization of these disorders by using a combination of strategies including cell biology, animal models, and by studying patients with these pathologic entities.

Azoospermia in a 46,XX/47,XXX phenotypic male

We report the unique case of a 34-year-old 46,XX/47, XXX man with complete masculinization and azoospermia. Analysis of the patient's deoxyribonucleic acid failed to detect the azoospermia factor (AZF) region. Lack of germ cell elements on subsequent testicular biopsy illustrates the importance of the AZF region for spermatogenesis. Discussion concerning the genetics of testicular and germ cell formation is undertaken in the context of the patient presented.

Phenotypical expression in XX males correlates with testicular response to exogenous choriogonadotropin in early infancy: does a variable degree of testicular failure determine the degree of genital ambiguity?

The 46,XX male syndrome is characterized by the presence of testicular development in subjects who lack a Y chromosome. The majority of patients have male external genitalia without ambiguity; however, 10-15% show diverse degrees of hypospadias. Testicular function is normal at birth but deteriorates thereafter. However, it has not been clarified why some cases exhibit genital ambiguity. This study examined 10 affected patients, including 4 prepubertal (< 1 year old) with hypospadias (1 glandular, 1 penile, and 2 penoscrotal). In all subjects, testicular function was evaluated by performing a stimulation with choriogonadotropin. In the postpubertal individuals, basal and poststimuli testosterone were below the reference values. Prepubertal patients had age-appropriate basal test-osterone concentrations. All responded to the choriogonadotropin challenge; however, the most significant response was observed in the patient with the glandular hypospadias, the second highest response was presented by the patient with the penile hypospadias, while both patients with the penoscrotal hypospadias had the poorest responses. These results suggest that the degree of genital ambiguity is correlated with the impairment in testosterone response to choriogonadotropin in early infancy, indicating a defect in testosterone production in XX males with genital ambiguity.

Molecular analysis in true hermaphrodites with different karyotypes and similar phenotypes

True hermaphroditism is characterized by the development of ovarian and testicular tissue in the same individual. Müllerian and Wolffian structures are usually present, and external genitalia are often ambiguous. The most frequent karyotype in these patients is 46,XX or various forms of mosaicism, whereas 46,XX is very rarely found. The phenotype in all these subjects is similar. We studied 10 true hermaphrodites. Six of them had a 46,XX chromosomal complement: 3 had been reared as males and 3 as females. The other 4 patients were mosaics: 3 were 46,XX/46,XY and one had a 46,XX/47,XXY karyotype. One of the 46,XX/46,XY mosaics was reared as a female, whereas the other 3 mosaics were reared as males. The sex of assignment in the 10 patients depended only on labio-scrotal differentiation. Molecular studies in 46,XX subjects documented the absence of Y centromeric sequences in all cases, arguing against hidden mosaicism. One patient presented Yp sequences (ZFY+, SRY+), which contrast with South African black 46,XX true hermaphrodites in whom no Y sequences were found. Molecular analysis in the subjects with mosaicism demonstrated the presence of Y centromeric and Yp sequences confirming the presence of a Y chromosome. Gonadal development, endocrine function, and phenotype in the 10 patients did not correlate with the presence of a Y chromosome or Y-derived sequences in the genome, confirming that true hermaphroditism is a heterogeneous condition.