Dysgenetic Testes Research Articles

Testicular dysgenesis syndrome: foetal origin of adult reproductive problems

The evidence for the existence of testicular dysgenesis syndrome (TDS) is presented in this review. Several epidemiological studies have shown that conditions like cryptorchidism, impaired spermatogenesis, hypospadias and testicular cancer can be associated as risk factors for each other. Thus, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis is that maternal exposure to endocrine disrupting chemicals may contribute to the pathogenesis of TDS. Animal experiments have shown that all TDS symptoms, except testicular cancer, can be induced by foetal exposure to anti-androgenic chemicals. However, the cause of TDS in humans remains to be determined.

Disorders of Sex Development

Objective: We studied the clinical profile, etiology, and outcome of patients with disorders of sex development (DSD). Design/Setting: Retrospective study/tertiary care hospital. Methods/Patients: All patients were registered in the Endocrine clinic of the Postgraduate Institute of Medical Education and Research, Chandigarh between 1995 and 2005. Results: Of 95 patients with DSD, 45 (47.4%) had 46, XX DSD, 45 (47.4%) had 46, XY DSD, while sex chromosomal DSD was identified in 4 (4.2%) and in one patient the disorder could not be defined. Forty-four patients (46.3%) had congenital adrenal hyperplasia (CAH), making it the most frequent cause for DSD. Of the 45 patients with 46, XX DSD, 37 patients (82.2%) had CAH and 6 (13.3%) had an ovotesticular DSD (true hermaphroditism). One patient had lower vaginal agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome variant) and another had 46, XX testicular DSD (XX male). Of the 45 patients with 46, XY DSD, 7 each (15.6%) had androgen insensitivity and CAH. Six (12.2%) had 5-α reductase deficiency, 4 (8.9%) had dysgenetic testes and 2 (4.4%) had a lutenizing hormone receptor mutation. Four patients (8.9%) had vanishing testes syndrome, and 3 (6.7%) had genital ambiguity associated with other congenital anomalies. One patient had 46 XY ovotesticular DSD. Two patients (4.4%) had bilateral cryptorchidism and 9 (20.0%) patients had idiopathic hypospadias. Four patients (4.2%) had sex chromosome DSD (mixed gonadal dysgenesis). Sex of rearing was concordant with genetic sex in all CAH patients except 9 genetic females with male gender identity, role, and orientation. The majority of patients with ovotesticular 46, XX DSD were reared as males. Sex of rearing and gender identity was concordant in all patients except in 3 patients with 5-α reductase deficiency who changed to male sex at puberty. One patient with undefined etiology presented with a lower abdominal mass that proved to be a gonadoblastoma, the only such tumor observed in our series. Social and cultural factors may have played a role on the sex of rearing even after explaining future fertility prospects. Conclusion: The clinical profile of various etiologies of DSD observed over the past 2 decades is presented using the recent classification. Forty-six, XX DSD was as common as that of 46 XY, DSD, and CAH was the most common cause of DSD. Sex of rearing in the majority of instances was influenced by social and cultural factors.

Dose‐dependent effects on cell proliferation, seminiferous tubules, and male germ cells in the fetal rat testis following exposure to di(n‐butyl) phthalate

Adult male rats gestationally exposed to di(n-butyl)phthalate (DBP) have dysgenetic testes characterized by seminiferous epithelial degeneration, clustering of Leydig cells, and decreased spermatogenesis. Cell proliferation and apoptosis are key processes regulating development of the testis, and alterations in these processes may underlie testicular dysgenesis. To determine whether gestational exposure to DBP affects cell proliferation and apoptosis in the developing rat testis. Pregnant dams were exposed to different dose levels of DBP in mid-gestation and cellular outcomes in fetal and early postnatal testes were assayed by histological and morphometric approaches. Gestational exposure to high dose DBP inhibited proliferation of fetal testicular somatic cells but did not affect apoptosis. Exposed fetal testes had a smaller volume and decreased cell numbers, with decreases in both the tubular and interstitial cell populations. A reduction was observed in the testis volume and altered seminiferous tubule morphometry at > or =50 mg/kg/d, and a decreased testicular cell number at > or =30 mg/kg/d DBP. The number of multinucleated gonocytes in DBP-exposed fetal testes increased after exposure to > or =100 mg/kg/d. The number of proliferating cells in the DBP-exposed testis rapidly rose after birth (when exposure stopped), and the testis volume and the total cell number was comparable to control by postnatal day 2. DBP reversibly inhibits proliferation of somatic cells in the fetal rat testis. Decreased proliferation, rather than increased apoptosis, is the underlying mechanism of altered fetal development of DBP-exposed seminiferous tubules contributing to testicular dysgenesis.

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.

Two cases of sex chromosomal mosaicism treated by laparoscopic gonadectomy

Two cases of sex chromosomal mosaicism treated by laparoscopic gonadectomy are described. Case 1 was a 23-year-old phenotypic female with primary amenorrhea. She had a history of a right inguinal herniorrhaphy at the age of 1 year and 3 months. Her external genitalia and vagina were normal, but chromosomal analysis showed mosaicism of 45X/46XY which comfirmed the diagnosis of mixed gonadal dysgenesis. A MRI demonstrated a small uterus and two high-intensity nodules near the orifice of both inguinal canals consistent with ectopic gonads. A laparoscopic bilateral gonadectomy was performed to avoid the risk of gonadoblastoma or dysgerminoma. The histopathologic study showed ovarian stromal cells lacking follicles and epithelial cells in the right gonad and a dysgenetic testis in the left nodule. Neither gonad contained neoplastic components. Case 2 was 28 years of age. She was diagnosed with Turner syndrome at the age of 2 years. Chromosomal analysis revealed a mosaic karyotype [45X/46X, idic(Y)]. Typical features of Turner syndrome, such as short statue, webbed neck, and a cubitus valgus deformity were observed. A MRI demonstrated a small uterus, but did not detect the location of the gonads. A laparoscopy was performed and streak gonads were identified adjacent to the oviducts bilaterally. Both gonads and oviducts were removed laparoscopically for prevention of neoplasm. The histopathologic examination revealed ovarian stromal cells without follicles and epithelial cells. Laparoscopy is helpful, not only to detect the location of gonads in patients with chromosomal abnormalities, but also to remove the structures with minimum invasion.

Talla baja en varones con fenotipo normal y mosaicismo 45,X/46,XY

There is wide variation in the clinical expression of 45,X/46,XY mosaicism. Ninety percent of prenatally diagnosed boys have normal male phenotype at birth, while those diagnosed postnatally show a wide spectrum of phenotypes, ranging from Turner syndrome, mixed gonadal dysgenesis, and male pseudohermaphroditism to apparent normality. We report the clinical, cytogenetic, endocrinologic and histologic findings in three boys with an apparently normal male phenotype and 45,X/46,XY mosaicism who were diagnosed postnatally because of their short stature. With the exception of one patient with Turner stigmata, no other abnormal features were found. No correlation between the proportion of 45,X/46,XY cell lines in blood, gonads and phenotype was found. Both prenatally and postnatally diagnosed boys with normal male phenotype must be followed-up because they can develop late-onset abnormalities, such as dysgenetic testes leading to infertility or neoplastic transformation, and short stature, which could be improved with growth hormone therapy.

A Man’s Brain in an Ambiguous Body: A Case of Mistaken Gender Identity

Chief complaint: “I feel like I have the brain of a man. Am I crazy?” On her first visit to a psychiatrist ( J.M.B.), “Ms. C,” a 48year-old woman, asked this question about her confused gender identity. Having also discovered a primary sexual attraction to women, Ms. C was having difficulty reconciling her church’s injunctions against sinful homosexual activities with her sense of herself as fundamentally male. She was dressed in a subtly frilly blouse and leather jacket she called “my leather-and-lace look.” Encircling each wrist were tattooed bracelets, traceries of curlicues and rosebuds that gently contradicted pearl earrings and a delicate gold locket. Born in the early 1950s and raised resolutely as a girl, Ms. C did not learn until she was 23 and married the unusual circumstances of her birth. Her mother finally divulged that she had entered the world with strange-looking genitals—neither male nor female. Doctors told her parents it was best to remove the odd tissue, fashion what remained to look female, and raise her as if nothing unusual had happened. At 6 months, surgeons removed both external tissue and presumed intra-abdominal testicular tissue and fashioned labia around the vaginal entrance she had always had. In grade school, she was told her large abdominal scar resulted from herniorrhaphy. At 12, after starting daily estrogen pills to induce puberty, she developed breasts and feminine curves, although without menarche or an increase in height beyond 5 feet. Her mother said she could not have children but did not explain why. She recalls being a tomboy who preferred boys for playmates. Because of her small stature and feminine appearance, however, boys were not particularly comfortable hanging out with her. Then, as now, she identified with the way males think rather than a sense of being physically male. She dated boys in high school, had a sexual experience with a woman during college, and married a man with whom she enjoyed satisfying marital relations for nearly two decades until they experienced a menage a trois. Her husband fell in love with the other woman, and she kindled awareness of her greater attraction to women than men. The marriage ended, and she embarked upon two long-term lesbian relationships and a struggle with alcoholism. Ms. C found sobriety and her church while that second relationship was unraveling. Welcomed and spiritually nurtured by church members, she felt happy except for increasing discontent with her pastor’s insistence that homosexual desires were her “cross to bear” and her options were either heterosexual marriage or celibacy. On one hand, her personal theology concurred that homosexuality was against God’s plan. On the other, she struggled with identifying herself as either man or woman, a dilemma her pastor could not solve. Ms. C’s childhood medical records had been lost. The psychiatrist asked if she had been karyotyped, given her unusual birth. She did not know. When she was born, chromosome testing was not routinely available. Given medical advice to raise her unquestioningly as a girl, the issue had not resurfaced. The psychiatrist suggested the test, and when results revealed 45,X/ 46,XY chromosomes, 75% the latter, the fragments—the childhood operation, hormones, her short stature, “brain of a man”—fell into place. She immediately reported feeling “less of a freak” now that she had a name—“intersexual”—for her condition.

A novel mutation in the accessory DNA-binding domain of human steroidogenic factor 1 causes XY gonadal dysgenesis without adrenal insufficiency

Steroidogenic factor 1 (SF1), officially designated NR5A1, is a nuclear receptor that plays key roles in endocrine development and function. Previous reports of human SF1 mutations revealed a spectrum of phenotypes affecting adrenal function and/or gonadal development and sex differentiation. We present the clinical phenotype and functional effects of a novel SF1 mutation. The patient is a 22-year-old 46, XY Japanese patient who presented with dysgenetic testes, atrophic vasa deferentia and epididymides, lack of Müllerian structures, and clitoromegaly. Endocrine studies revealed normal adrenal function. Analysis of the SF1 gene revealed compound heterozygosity for a previously described p.G146A polymorphism and a novel missense mutation (p.R84C) in the accessory DNA-binding domain. The father carried the p.G146A polymorphism and the mother had the p.R84C mutation; both were clinically and reproductively normal. Functional studies demonstrated that the p.R84C SF1 had normal nuclear localization but decreased DNA-binding affinity and transcriptional activity compared with wild-type SF1; it did not exhibit any dominant negative activity. These results describe the human phenotype that results from compound heterozygosity of the p.G146A polymorphism and a novel p.R84C mutation of SF1, thereby extending the spectrum of human SF1 mutations that impair testis development and sex differentiation in a sex-limited manner while preserving normal adrenal function.

High incidence of Y-chromosome microdeletions in gonadal tissues from patients with 45,X/46,XY gonadal dysgenesis

A higher incidence of Y-chromosome microdeletions was found on gonadal DNA than on peripheral blood lymphocyte DNA and on streak gonads than on dysgenetic testis in 11 patients with 45,X/46,XY gonadal dysgenesis. It is probable that an association between Y-chromosome microdeletions and severity of the phenotype in 45,X/46,XY patients exists.

Surgical, Medical and Psychological Dilemmas of Sex Reassignment: Report of a 46,XY Patient Assigned Female at Birth

This is a report of a 16 year-old 46,XY male who was reassigned female and had feminizing surgery during infancy because of what was judged to be inadequate genital masculinization. This patient had a dysgenetic testis that was shown to be producing testosterone during infancy. Although initially the reassignment appeared to be successful, psychological problems became progressively more severe during childhood to incapacitation by age 10 years. After it was verified that he had a male sexual identity, reassignment as male began, initially by living as a boy, then with testosterone therapy. Staged phalloplasty surgery was begun at age 16 years. Currently he has an adult-sized penis, although its function is not yet clear. Sadly, none of the steps to align his sex assignment to his perception as male has significantly alleviated his psychological issues and he continues to be severely impaired and socially compromised. Major issues include the crippling psychiatric disease that is resistant to psychotherapy and surgical problems with phalloplasty after surgery at infancy that involved reduction of the phallus with recession of the glans to the typical clitoral location. The glans was left intact at the anterior base of the phallus. Genital responsiveness during sexual activity and satisfaction are as yet unknown.

A rare diagnosis: testicular dysgenesis with carcinoma in situ detected in a patient with ultrasonic microlithiasis

A rare case is presented where a dysgenetic testis with microinvasive carcinoma in situ (CIS, also known as intratubular germ cell neoplasm of unclassified type [IGCNU] and testicular intraepithelial neoplasia [TIN]) with microinvasion to rete testis and the interstitial tissue was found in a 32-year-old man presenting with mild scrotal pain and ultrasonic testicular microlithiasis. Knowledge of the association of ultrasound and CIS is important to diagnose patients at the stage prior to development of an overt germ cell tumor. The patient had three of four disorders considered symptoms of the testicular dysgenesis syndrome (TDS): a dysgenetic left testicle with CIS, a mild left-sided cryptorchidism (high positioned scrotal hypotrophic testis) and a slightly reduced semen quality. Therefore, it should be kept in mind that a patient with one TDS symptom may harbour the other, even CIS or testicular cancer. Accordingly, patients with one TDS symptom ought to be examined for the presence of the others, and if more that one is present, extra concern is warranted.

The anatomy of the caudal vas deferens in patients with a genital anomaly

Objective To present a hypothesis to explain the various anatomical variants of children with both a vas deferens and retained vagina. Materials and methods A child with both vasa entering into a blind-ending vaginal sinus opening into the prostatic urethra is presented, followed by a review of studies published in English describing children with a vas deferens and a retained vagina, and normal and abnormal vaginal development. Results The caudal end of the vas deferens and its relationship to a retained vagina are not well described in the literature. Adequate exocrine levels of androgen inside the Wolffian duct may allow its preservation in conjunction with a related vagina (secondary to inadequate endocrine levels of androgen), with incorporation of the vas into the vaginal wall. Conclusions We propose that testosterone and Müllerian-inhibiting substance/anti-Müllerian hormone reach the Wolffian and Müllerian ducts by exocrine passage through the Wolffian duct. Thus, where the gonad is a dysgenetic testis the ipsilateral Wolffian duct will be preserved in proportion to the amount of testosterone available. Where a fetus has adequate exocrine secretion of androgen down the Wolffian duct, but inadequate endocrine blood levels of androgen, the vas deferens and vagina can coexist, with incorporation of the vas into the wall of the vagina.

Distribution of Y-chromosome-bearing cells in gonadoblastoma and dysgenetic testis in 45,X/46,XY infants

Gonadoblastoma is an unusual mixed germ cell–sex cord–stromal tumor that has the potential for malignant transformation and 30% of all patients with gonadoblastoma develop germ cell tumors mainly dysgerminoma/seminoma. An additional 10% gives rise to other malignant germ cell neoplasms. This tumor affects a subset of patients with intersex disorders. The age at diagnosis is variable ranging from birth to the fourth decade, but around 94% of cases are diagnosed during the first three decades of life and there are few cases with gonadoblastoma diagnosed in infants. In this paper, we present the histological and molecular findings of four patients with gonadal dysgenesis who developed gonadoblastoma in the first 2 years of life and one case with bilateral dysgerminoma diagnosed at 15 years of age. The sex chromosomes of mosaic patients do not distribute homogenously in dysgenetic gonads; however, statistical analysis of FISH results revealed significant differences between the XY cell line in the gonadoblastoma compared with the dysgenetic testis. Our cases demonstrate that tumors could be present at a very early age, so the prophylactic removal of the gonads is advised.

True Hermaphroditism with Characteristics of Klinefelter's Syndrome: A Rare Presentation

True hermaphroditism, a very rare cause of intersex, is usually diagnosed during the newborn period in the course of evaluating ambiguous genitalia. As an exception we report an unusual case of a 14.5 year-old boy with phenotypically near-normal male genitalia and bilaterally descended gonads, who was seen for evaluation of gynecomastia and hematuria. His eunuchoid body habitus and mild mental retardation were compatible with Klinefelter's syndrome. He had a low level of free testosterone (15.2 pmol/l), and high level of estradiol (264.3 pmol/l) for his age. The patient was diagnosed as true hermaphroditism with 46,XX /47,XXY karyotype causing an ovotestis with inguinal uterus hernia in the left scrotum and a dysgenetic testis in the right scrotum.

Unusual mixed gonadal dysgenesis associated with Müllerian duct persistence, polygonadia, and a 45,X/46,X,idic(Y)(p) karyotype

Mixed gonadal dysgenesis (MGD) is a developmental anomaly in which most of the patients have a dysgenetic testis, a contralateral streak and a 45,X/46,XY karyotype. This entity involves an heterogeneous group of gonadal and phenotypic abnormalities with a wide clinical spectrum. The phenotype depends on the ratio of testicular tissue which induces virilization. Although the karyotype in these patients is 45,X/46,XY, no genotype-phenotype correlation has been found to date. Müllerian ducts persistence (MDP) in MGD is rare; however, four patients with both entities and different karyotypes have been described. Here we present the data on a newborn patient with an atypical MGD associated with MDP, two left testes, a gonadal streak on the right, and absence of Wolffian derivatives. PCR analysis identified all the Y-derived sequence tested in the father, while the patient had them all except the AZF b,c regions which were lost. FISH analysis of the paternal Y chromosome documented Yq paracentric inversion while the patient's karyotype was 45,X/46,X,idic(Yp). No mutations were observed in MIS/MISRII genes.

Testicular Dysgenesis without Adrenal Insufficiency in a 46,XY Patient with a Heterozygous Inactive Mutation of Steroidogenic Factor-1

Steroidogenic factor-1 (SF-1) regulates multiple genes involved in the adrenal and gonadal development and in the biosynthesis of a variety of hormones, including adrenal and gonadal steroids, anti-Mullerian hormone (AMH), and gonadotropins. We identified a novel SF-1 mutation in a 27-yr-old Japanese patient with a 46,XY karyotype. Sequence analysis was performed for all the seven exons of SF-1, revealing a heterozygous single base pair deletion at exon 2 (18delC) that is predicted to cause a frameshift at the sixth codon and resultant termination at the 74th codon. Functional studies showed that the mutation produced no demonstrable protein and had no transcription activity or dominant negative effect. Clinical features included small dysgenetic testes with vasa deferentia and epididymides, absent uterus, blind-ending vagina, clitoromegaly, and psychosexual disturbance. Endocrine studies showed normal adrenal function (cortisol response to ACTH stimulation, 13.4-->25.3 microg/dl) and primary hypogonadism (testosterone response to hCG stimulation, 0.57-->0.76 ng/ml; gonadotropin responses to GnRH stimulation: LH, 10-->59 mIU/ml; FSH, 36-->69 mIU/ml), and urinary steroid hormone profile analysis indicated grossly normal steroidogenic enzyme activities. The results suggest that SF-1 haploinsufficiency can selectively impair testicular development and permit the biosynthesis of AMH and testosterone in dysgenetic testes and the production of gonadotropins in pituitary gonadotropes.

Alterations of sex differentiation in males: from candidate genes to diagnosis and treatments.

Sex, that is, whether one is physically male or female, is the basic dichotomy of life. Sex is important not only for reproductive role, but also for physical attributes, personal identity and disease susceptibility. Sex determination is genetically controlled, with the key event in males being the transmission of a Y chromosome from father to offspring. The sex-determining gene on the Y chromosome, SRY, triggers the expression of a repertoire of other genes that cause the undifferentiated gonad to develop as a testis. Hormones secreted by the developing testis cause the internal and external genitalia to masculinize. Testicular development is disrupted by de novo or inherited genetic alterations leading to gonadal dysgenesis. Decreased hormone production from dysgenetic testes disrupts the normal development of the internal and external genitalia. Incomplete masculinization of the genitalia also occurs from hormonal biosynthetic defects or decreased response to hormones from inherited receptor defects. Treatment is tailored to the individual diagnosis and may include removal of dysgenetic gonads, surgical correction of incompletely masculinized genitalia, replacement of deficient hormones, and, in some instances, gender reassignment.

Clinical management and molecular cytogenetic characterization in a 45,X/46,X,idic(Yp) patient with severe hypospadia

Cryptorchidism and proximal hypospadia in a newborn are highly suspicious for an intersex disorder, and proper investigations should be planned immediately after birth. In some hypospadic patients, the presence of a palpable gonad in the scrotum may induce to assign the male sex, whereas the anatomy of internal and external genitalia could be extremely complex, requiring an accurate evaluation before any definitive attribution of gender. The authors present a case of an infant, referred to the hospital for surgical treatment of a proximal hypospadia, who showed ambiguous external genitalia, absence of the right gonad, a partially dysgenetic left testis, and presence of both müllerian and wolffian structures. Cytogenetic analysis detected a mosaicism with a cell line showing an isodicentric Yp chromosome and a second one, a 45, X chromosomal complement. Because the baby had been assigned previously to male gender, he underwent a staged masculinizing correction of the genital anomalies. The authors discuss the necessity of a careful evaluation of these patients at birth by a multispecialistic team, for appropriate sex assignment and for the assessment of the risk of neoplastic degeneration.

Pediatric surgical images: Mixed gonadal dysgenesis

MIXED GONADAL dysgenesis is an intersex disorder often characterized by gonadal asymmetry with a dysgenetic testis on one side and a streak gonad on the contralateral side. Patients usually have 45X/46XY mosaicism. The dysgenetic gonad is known to have an increased risk for gonadoblastoma; therefore, the gonad often is removed, and female reconstruction is performed followed by hormone replacement therapy. Retained Müllerian remnants are common. Some features of Turner’s syndrome including shortness of stature are common, and this, along with the presence of a small phallus, has led to many patients being assigned the female gender and reconstructed as female. A more conservative approach to gender assignment has more recently been considered. If the phallus is sufficiently masculinized and the hypospadias is reparable, male reconstruction with male hormone replacement therapy is an option. As the child approaches puberty, hormone studies should be performed to assess the functional capability of the testis. If there is a deficiency, hormone supplementation may be necessary during puberty.

FISH and PCR analyses in three patients with 45,X/46,X,idic(Y) karyotype: clinical and pathologic spectrum

Objective. – To delineate the phenotypic spectrum (clinical and gonadal features) from patients with a 45,X/46,X,mar(Y) karyotype based upon of their clinical, histological, cytogenetic and molecular evaluation. Subjects. – Three patients with a 45,X/46,X,mar(Y) karyotype. Methods. – Clinical assessment, karyotyping, endocrine evaluation, FISH and PCR analyses of several Y-chromosome loci and direct sequencing of the SRY gene. Results. – The patients, two males and one female had varying degrees of impairment of sexual differentiation, with or without testis formation. One patient (reared as female and aged 17 years) had Turner syndrome with bilateral streak gonads. The second patient (2.4 years old) had ambiguous genitalia and presented a dysgenetic testis with a contralateral streak gonad. A third patient (26 years old) had bilateral dysgenetic testes (dysgenetic male pseudohermaphroditism). The ratio of 45,X vs. 46,X,+mar(Y) cells differed between patients and between different tissues. In each case the marker sexual chromosome was identified as a rearranged Y-chromosome (idic(Y)) using FISH and PCR analyses. In all cases the SRY gene was present in all tissues studied. No mutations were identified in this gene in any of the patients. Conclusions. – The extent of male or female differentiation in these patients depends in part on the prevalence, time occurrence, and distribution of the 45,X cell line.