46,XX testicular disorder of sexual development with SRY-negative caused by some unidentified mechanisms: a case report and review of the literature

Copy number variations (CNVs) and karyotyping analysis in males with azoospermia and oligospermia

BACKGROUND

Considering the essential roles that genetic factors play in azoospermia and oligospermia, this study aims to identify abnormal chromosomes using karyotyping and CNVs and elucidate the associated genes in patients.

METHODS

A total of 1157 azoospermia and oligospermia patients were recruited, of whom, 769 and 674 underwent next-generation sequencing (NGS) to identify CNVs and routine G-band karyotyping, respectively.

RESULTS

First, 286 patients were co-analyzed using CNV sequencing (CNV-seq) and karyotyping. Of the 725 and 432 patients with azoospermia and oligospermia, 33.8% and 48.9% had abnormal karyotypes and CNVs, respectively. In particular, 47,XXY accounted for 44.18% and 26.33% of abnormal karyotypes and CNVs, respectively, representing the most frequent genetic aberration in azoospermia and oligospermia patients. Nevertheless, big Y and small Y accounted for 7.46% and 16.67% of abnormal karyotypes, respectively. We also identified high-frequency CNVs-loci, such as Xp22.31 and 2p24.3, in azoospermia and oligospermia patients.

CONCLUSION

Sex chromosome and autosomal CNV loci, such as Xp22.31 and 2p24.3, as well as the associated genes, such as VCX and NACAP9, could be candidate spermatogenesis genes. The high-frequency abnormal karyotypes, CNV loci, and hot genes represent new targets for future research.

Optical Genome Mapping for a Patient with a Congenital Disorder and Chromosomal Translocation

We performed optical genome mapping (OGM), a newly developed cytogenetic technique, for a patient with a disorder of sex development (DSD) and a 46,XX,t(9;11)(p22;p13) karyotype. The results of OGM were validated using other methods. OGM detected a 9;11 reciprocal translocation and successfully mapped its breakpoints to small regions of 0.9-12.3 kb. OGM identified 46 additional small structural variants, only three of which were detected by array-based comparative genomic hybridization. OGM suggested the presence of complex rearrangements on chromosome 10; however, these variants appeared to be artifacts. The 9;11 translocation was unlikely to be associated with DSD, while the pathogenicity of the other structural variants remained unknown. These results indicate that OGM is a powerful tool for detecting and characterizing chromosomal structural variations, although the current methods of OGM data analyses need to be improved.

A rare case of male sex reversal syndrome (46, XX) with negative SRY gene: a disorder of sexual differentiation (DSD)

Background

Male sex reversal syndrome is a rare genetic cause of male infertility with an overall incidence of 1/20,000–1/100,000 males. There is mismatching between the genetic make-up and the apparent clinical features. The clinical presentation of such cases is variable ranging from ambiguous genitalia at birth, failed puberty, up to normal male phenotype with infertility and hypogonadism. The exact molecular and genetic bases of this syndrome are still unclear. Most of the recorded cases were SRY positive (i.e. representing 80–90% of all cases), and they showed translocated SRY gene on the Y chromosome. Moreover, fewer cases of male sex reversal (46, XX) were SRY negative.

Case presentation

Herby, we report a rare case of a 35-year-old infertile male patient who presented with azoospermia, hypergonadotropic hypogonadism, and abnormal classical (46, XX) karyotype, as well as negative FISH for SRY gene. He had a previous negative biopsy and was asking for redoing micro-TESE, whoever he was discouraged as chances to find sperm is eventually nil, and instead, he was prescribed testosterone replacement therapy to correct hypogonadism.

Conclusion

Therefore, any case of non-obstructive azoospermia should be offered genetic testing trying to exclude non-treatable cases and for genetic counseling.

SRY-negative 46,XX testicular/ovotesticular DSD: Long-term outcomes and early blockade of gonadotropic axis

OBJECTIVE

SRY-negative 46,XX testicular and ovotesticular disorders/differences of sex development (T/OTDSD) represent a very rare and unique DSD condition where testicular tissue develops in the absence of a Y chromosome. To date, very few studies have described the phenotype, clinical and surgical management and long-term outcomes of these patients. Particularly, early blockade of the gonadotropic axis in patients raised in the female gender to minimize postnatal androgenization has never been reported.

DESIGN

Retrospective description of sixteen 46,XX T/OTDSD patients.

RESULTS

Sixteen 46,XX SRY-negative T/OTDSD were included. Most (12/16) were diagnosed in the neonatal period. Sex of rearing was male for six patients and female for ten, while the clinical presentation varied, with an external masculinization score from 1 to 10. Five patients raised as girl were successfully treated with GnRH analog to avoid virilization during minipuberty. Ovotestes/testes were found bilaterally for 54% of the patients and unilaterally for the others (with a contralateral ovary). Gonadal surgery preserved appropriate tissue in the majority of cases. Spontaneous puberty occurred in two girls and one boy, while two boys required hormonal induction of puberty. One of the girls conceived spontaneously and had an uneventful pregnancy. DNA analyses (SNP-array, next-generation sequencing and whole-exome sequencing) were performed. A heterozygous frameshit mutation in the NR2F2 gene was identified in one patient.

CONCLUSIONS

This study presents a population of patients with 46,XX SRY-negative T/OTDSD. Early blockade of gonadotropic axis appears efficient to reduce and avoid further androgenization in patients raised as girls.

Erectile function in SRY positive 46,XX males with normal phenotype

Introduction

The 46,XX male syndrome is a rare disorder of sex development and has two different forms, depending on the sex-determining region's presence on the Y chromosome (SRY) gene. The SRY positive 46,XX males are usually diagnosed during infertility workup. We evaluated the erectile function of 46,XX SRY positive males and compared it with healthy males.

Material and methods

Ten patients with azoospermia and 46,XX SRY positive disorder who referred to a urology clinic with infertility were analyzed retrospectively. Controls were chosen from healthy males at similar ages. The physical examination was performed, and serum hormones were obtained at admission. The clinical assessment of erectile dysfunction was evaluated by the International Index of Erectile Function (IIEF) questionnaire.

Results

There was no statistically significant difference between the two groups in terms of age, serum prolactin, luteinizing hormone (LH) levels and IIEF scores (P >0.05). In 46,XX males, serum follicle-stimulating hormone (FSH) levels were significantly higher, and total testosterone levels and testicular volumes were found to be significantly lower when compared to controls (p <0.001, p <0.05, p <0.01, respectively).

Conclusions

This study indicates that these males' erectile function is similar to those of 46,XY males.

A Rare Presentation of Disorder of Sex Development

Disorder of sex development (DSD) is the term ascribed to a wide group of disorders presenting with congenital discord between chromosomal sex and phenotypic manifestation. Its incidence is 1 in 4500 births. 46 XX testicular DSD is a rare disorder characterized by the discordance between female karyotype and male phenotype. Its incidence is 1:20,000 to 25,000 male infants. It is further classified into SRY positive and SRY negative individuals, depending on the presence or absence of sex-determining region Y gene (SRY) on the X chromosome as a result of translocation. We are hereby reporting a rare case of de la Chapelle syndrome (SRY negative). A 30-year-old phenotypical male presented to us with complaints of primary infertility. He had had hypospadias during his childhood and underwent corrective surgery at the age of 18 years. For the previous 1.5 years, he had been complaining of decreased libido, difficulty in micturition, and presence of watery ejaculate. On examination, he had bilateral palpable testis with the testicular volume of 7 mL each, curved micropenis with chordee, and eccentric meatus with fistula. Semen analysis revealed azoospermia and hormonal profile was consistent with hypergonadotropic hypogonadism. His karyotyping turned out to be 46 XX chromosome without the SRY gene on polymerase chain reaction (PCR) array. He was medically treated with testosterone and underwent surgical correction of chordee.  The SRY negative testicular 46 XX disorder is a rare expression and can be diagnosed at the time of birth with the presence of severe hypospadias, cryptorchidism, or ambiguous genitalia. All new-borns with these findings should undergo evaluation for the disorder of sexual development. Such individuals can never father a child and genetic counseling should be offered. Infertility is the main concern for such individuals which can be addressed by in vitro fertilization (IVF) with a sperm donor or adoption.

An Unusual Case of Testicular Disorder in Sex Development of Arabian Mare (64,XX SRY-Negative)

Simple Summary

An interesting case of a horse with an XX, SRY-negative disorder of sexual development (DSD) is reported in this paper. In particular, the animal showed the development of both male and female portions of reproductive organs. The possible genetic background of this abnormality is also discussed.

Abstract

A 3-year-old Arabian mare underwent medical examinations due to the presence of abnormalities of the reproductive apparatus and stallion behavior (nervous temperament, aggressiveness, masculine attitude). During the clinical visit, an anovulvar distance shorter than normal was observed; moreover, vulvar lips were dorsally fused except for the lower neckline, showing a blind ending from which a penis-like structure protruded. The ultrasound examination revealed the presence of a cervix and corpus of a uterus, hypoplastic uterine horns, and small gonads with an echogenicity similar to a testis. Blood testosterone levels ranged from 0.4 to 0.6 ng/mL. Cytogenetic analysis showed a normal female karyotype (2n = 64,XX), while PCR amplification of SRY and ZFY genes revealed the absence of a Y chromosome. At necroscopic examination, internal genitalia arising from the genital ridge in the form of masculine type structures were found, while those deriving from the Mullerian ducts were of feminine type. In addition, an infundibular portion of the salpinx at the cranial pole of the gonads was found. This is the first case in equine species of DSD 2n = 64,XX SRY-negative, with the simultaneous presence of male (hypoplastic testicles, epididymal portions, and a penis-like structure) and female (cervix, horn and body of a hypoplastic uterus) genital structures.

Male patient 46,XX SRY-negative and unambiguous genitalia: A case report

En la mayoría de los casos, la diferenciación sexual masculina ocurre con la participación del gen SRY. Sin embargo, se pueden presentar otros genotipos excepcionales, como en el caso que se presenta en este reporte.

Se trata de un paciente adulto de sexo masculino atendido en el Servicio de Paternidades del Instituto de Genética de la Universidad Nacional de Colombia. Se le hicieron los análisis del gen de la amelogenina y de repeticiones cortas en tándem (Short Tandem Repeat, STR) específicas para el gen SRY con estuches comerciales de identificación humana, así como los de cariotipo convencional e hibridación in situ fluorescente del SRY, y el estudio de microdeleciones del cromosoma Y mediante reacción en cadena de la polimerasa (PCR). Se le hizo la evaluación clínica y se le brindó asesoramiento genético. El paciente no presentaba ambigüedad genital, su cariotipo era 46 XX, y el perfil molecular era negativo para el gen SRY y positivo para el ZFY. Se le diagnosticó un trastorno de diferenciación sexual 46 XX testicular no sindrómico, una rara condición genética. Solo el 20 % de los pacientes con este diagnóstico son negativos para SRY y exhiben perfiles moleculares diversos. La información disponible parece indicar que el ZFY está relacionado con la diferenciación sexual masculina, aún en ausencia del gen SRY.

Molecular cytogenetic analysis and genetic counseling: a case report of eight 46,XX males and a literature review

Background

46,XX male syndrome is a rare disorder that usually causes infertility. This study was established to identify the genetic causes of this condition in a series of 46,XX males through the combined application of cytogenetic and molecular genetic techniques.

Case presentation

We identified eight azoospermic 46,XX males who underwent infertility-related consultations at our center. They all presented normal male phenotypes. In seven of the eight 46,XX males (87.5%), translocation of the SRY gene to the terminal short arm of the X chromosome was clearly involved in their condition, which illustrated that this translocation is the main mechanism of 46,XX sex reversal, in line with previous reports. However, one patient presented a homozygous DAX1 mutation (c.498G > A, p.R166R), which was not previously reported in SRY-negative XX males.

Conclusions

We proposed that this synonymous DAX1 mutation in case 8 might not be associated with the activation of the male sex-determining pathway, and the male phenotype in this case might be regulated by some unidentified genetic or environmental factors. Hence, the detection of genetic variations associated with sex reversal in critical sex-determining genes should be recommended for SRY-negative XX males. Only after comprehensive cytogenetic and molecular genetic analyses can genetic counseling be offered to 46,XX males.

Two-Stage Urethroplasty with Buccal Mucosa for Penoscrotal Hypospadias Reconstruction in a Male with a 46,XX Karyotype

We present a case regarding a 32-year old African male with penoscrotal hypospadias, left cryptorchidism and a left inguinal hernia. There were moderate masculinization characteristics. He underwent a Lichtenstein hernia repair with perioperative biopsies of the left inguinal testis and epididymis. Microscopic examination showed a Sertoli-only left testis with Leydig-cell hyperplasia and the left epididymis consisted of ovarian tissue with corpora albicantia and maturing follicles. Endocrinological evaluation showed a sex-determining region Y (SRY) negative 46,XX karyotype. We successfully performed a two-stage urethroplasty with buccal mucosa graft to reconstruct his penoscrotal hypospadias.

NR5A1 is a novel disease gene for 46,XX testicular and ovotesticular disorders of sex development

PURPOSE

We aimed to identify the genetic cause in a cohort of 11 unrelated cases and two sisters with 46,XX SRY-negative (ovo)testicular disorders of sex development (DSD).

METHODS

Whole-exome sequencing (n = 9), targeted resequencing (n = 4), and haplotyping were performed. Immunohistochemistry of sex-specific markers was performed on patients' gonads. The consequences of mutation were investigated using luciferase assays, localization studies, and RNA-seq.

RESULTS

We identified a novel heterozygous NR5A1 mutation, c.274C>T p.(Arg92Trp), in three unrelated patients. The Arg92 residue is highly conserved and located in the Ftz-F1 region, probably involved in DNA-binding specificity and stability. There were no consistent changes in transcriptional activation or subcellular localization. Transcriptomics in patient-derived lymphocytes showed upregulation of MAMLD1, a direct NR5A1 target previously associated with 46,XY DSD. In gonads of affected individuals, ovarian FOXL2 and testicular SRY-independent SOX9 expression observed.

CONCLUSIONS

We propose NR5A1, previously associated with 46,XY DSD and 46,XX primary ovarian insufficiency, as a novel gene for 46,XX (ovo)testicular DSD. We hypothesize that p.(Arg92Trp) results in decreased inhibition of the male developmental pathway through downregulation of female antitestis genes, thereby tipping the balance toward testicular differentiation in 46,XX individuals. In conclusion, our study supports a role for NR5A1 in testis differentiation in the XX gonad.Genet Med 19 4, 367-376.