The XY gonadal agenesis syndrome

MYRF haploinsufficiency causes 46,XY and 46,XX disorders of sex development: bioinformatics consideration

Disorders of sex development (DSDs) are defined as congenital conditions in which chromosomal, gonadal or anatomical sex is atypical. In many DSD cases, genetic causes remain to be elucidated. Here, we performed a case-control exome sequencing study comparing gene-based burdens of rare damaging variants between 26 DSD cases and 2625 controls. We found exome-wide significant enrichment of rare heterozygous truncating variants in the MYRF gene encoding myelin regulatory factor, a transcription factor essential for oligodendrocyte development. All three variants occurred de novo. We identified an additional 46,XY DSD case of a de novo damaging missense variant in an independent cohort. The clinical symptoms included hypoplasia of Müllerian derivatives and ovaries in 46,XX DSD patients, defective development of Sertoli and Leydig cells in 46,XY DSD patients and congenital diaphragmatic hernia in one 46,XY DSD patient. As all of these cells and tissues are or partly consist of coelomic epithelium (CE)-derived cells (CEDC) and CEDC developed from CE via proliferaiton and migration, MYRF might be related to these processes. Consistent with this hypothesis, single-cell RNA sequencing of foetal gonads revealed high expression of MYRF in CE and CEDC. Reanalysis of public chromatin immunoprecipitation sequencing data for rat Myrf showed that genes regulating proliferation and migration were enriched among putative target genes of Myrf. These results suggested that MYRF is a novel causative gene of 46,XY and 46,XX DSD and MYRF is a transcription factor regulating CD and/or CEDC proliferation and migration, which is essential for development of multiple organs.

Undescended testis - current trends and guidelines: a review of the literature

The best mode of undescended testis (UDT) treatment remains controversial. However, knowledge gained from randomized controlled studies and meta-analyses allowed different groups of researchers to set out guidelines on management of patients with UDT. The authors reviewed recent literature and came to the following conclusions: (1) Hormonal treatment is not recommended, considering both the immediate results (only 15-20% of retained testes descend) and the possible long-term adverse effects on spermatogenesis. (2) Surgery is the treatment of choice; orchiopexy is successful in about 95% of UDT, with a low rate of complications (about 1%). (3) Orchiopexy should be performed between 12 and 18 months of age, or at first contact if diagnosed later.

Clinical, biological and genetic analysis of anorchia in 26 boys

Background

Anorchia is defined as the absence of testes in a 46,XY individual with a male phenotype. The cause is unknown.

Methods

We evaluated the clinical and biological presentation, and family histories of 26 boys with anorchia, and sequenced their SRY, NR5A1, INSL3, MAMLD1 genes and the T222P variant for LGR8.

Results

No patient had any associated congenital anomaly. At birth, testes were palpable bilaterally or unilaterally in 13 cases and not in 7; one patient presented with bilateral testicular torsion immediately after birth. The basal plasma concentrations of anti-Müllerian hormone (AMH, n = 15), inhibin B (n = 7) and testosterone (n = 19) were very low or undetectable in all the patients evaluated, as were the increases in testosterone after human chorionic gonadotropin (hCG, n = 12). The basal plasma concentrations of follicle stimulating hormone (FSH) were increased in 20/25, as was that of luteinising hormone in 10/22 cases. Family members of 7/26 cases had histories of primary ovarian failure in the mother (n = 2), or sister 46,XX, together with fetal malformations of the only boy with microphallus and secondary foot edema (n = 1), secondary infertility in the father (n = 2), or cryptorchidism in first cousins (n = 2). The sequences of all the genes studied were normal.

Conclusion

Undetectable plasma concentrations of AMH and inhibin B and an elevated plasma FSH, together with 46,XY complement are sufficient for diagnosis of anorchia. The hCG test is unnecessary. NR5A1 and other genes implicated in gonadal development and testicle descent were not mutated, which suggests that other genes involved in these developments contribute to the phenotypes.

Clinical pathologic correlation: primary amenorrhoea and bilateral adnexal tumors

A case of bilateral gonadoblastoma in 46,XY gonadal dysgenesis is presented and discussed by both clinician and pathologist, in this traditional clinico-pathologic conference. The discussion includes the differential diagnoses of primary amenorrhoea.

46, XY agonadism associated with adrenal adenoma/myelolipoma: report of a case analyzing Y-chromosome-specific sequences

A unique patient with 46, XY agonadism associated with adrenal adenoma/myelolipoma is described. The patient was an 18-year-old female with primary amenorrhea, lack of secondary sexual development and an aldosterone-producing adrenocortical adenoma associated with foci of myelolipoma. Molecular analyses of Y-chromosome-specific regions, including automated sequencing of the entire coding region of SRY, the Y-linked testis-determining gene, were performed. Our results excluded the possibility that a mutation in SRY was responsible for this unusual clinical combination.

Low birth-weight, microcephalic malformation syndrome in a 46,XX girl and her 46,XY sister with agonadism: third report of the Kennerknecht syndrome or autosomal recessive Seckel-like syndrome with previously undescribed genital anomalies

We report on two sisters, one 46,XX with normal female phenotype, the other 46,XY with ambiguous external genitalia and agonadism. Both have a low birth weight and microcephalic malformation syndrome leading to early death. The 46,XX patient also had a diaphragmatic defect. The XY sister, in addition to absence of gonads and Mùllerian and Wolffian derivatives, had severe hypoplasia of the pulmonary artery and its branches, multicystic kidneys, and pachygyria. This combination of malformations, in part, fits in the autosomal recessive condition described by Kennerknecht et al. [1993] in a 46,XX and 46,XY pair of sibs with agonadism. The craniofacial appearance of our patients is similar to that observed in the 46,XY sister with agonadism reported by Kennerknecht et al. [1995]. On the other hand, intrauterine growth retardation, microcephaly, and pachygyria are not part of the phenotype of the Kennerknecht "syndrome" and agonadism was not present in our 46,XX patient. We suggest two hypotheses to explain the abnormal phenotype in our cases. The first is that they might represent the third sibship affected by the Kennerknecht syndrome with additional anomalies. Alternatively, our two sibs might have a Seckel or a Seckel-like syndrome. The 46,XY patient would then be the first case of Seckel syndrome with sex reversal and agonadism.

[From pathological diagnosis to ovulation induction. The case of ovarian insufficiency]

The incidence of premature ovarian failure (POF) is around 1 to 3%. This pathology occurs in young women, who often wish to become pregnant. Theoretically, two mechanisms could be involved: initial follicle depletion and follicle dysfunction. However, in some cases, mixed mechanisms are involved. Initially, PFO was considered irreversible. In fact, signs of intermittent ovarian function in normal karyotypically women have been described, but predicting the probability of spontaneous remission in a specific woman is impossible. Therefore, various treatments for ovulation induction have been proposed to these patients. Most of the pregnancies occur after hormone replacement therapy. The action of this treatment is unclear and the cause-and-effect relation has not been proven by prospective, randomized studies. The benefit of suppressing endogen gonadotropins by GnRH agonists is not proven either. Estrogen supplementation and high-dose gonadotropin ovarian stimulation protocols have been proposed. Even so, this therapy cannot be recommended because of the lack of controlled studies. Finally, numerous case reports have described the return of ovarian function after using immunosuppressive therapies. The lack of particular criteria for the diagnosis of autoimmune mechanisms have lead to treat heterogeneous groups of patients. No randomized controlled studies with immunologic monitorage have been performed that could establish the success of this therapy. Therefore, in order to find effective treatments, basic pathophysiologic mechanisms must be better understood. For those women who want to become pregnant, the lack of prospective, randomized studies cannot lead to formal conclusions. Depending on the patients' age and history, it appears reasonable to attempt a corrective therapy based on defined etiology, before entering in a donor oocyte program.

Ovarian differentiation and gonadal failure

Ovarian failure can result from several different genetic mechanisms-X chromosomal abnormalities, autosomal recessive genes causing various types of XX gonadal dysgenesis, and autosomal dominant genes. The number and precise location of loci on the X are still under investigation, but it is clear that, in aggregate, these genes are responsible for ovarian maintenance, given that monosomy X shows germ cells that undergo accelerated atresia. Despite recent hypotheses, at present there is no evidence for a gene directing primary ovarian differentiation; this process may be constitutive. Phenotypic/karyotypic correlation and limited molecular confirmation have long shown that proximal Xp and proximal Xq contain regions of the most importance to ovarian maintenance. Terminal deletions at Xp11 result in 50% primary amenorrhea and 50% premature ovarian failure or fertility. Deletions at Xq13 usually produce primary amenorrhea. Terminal deletions nearer the telomeres on either Xp of Xq bring about premature ovarian failure more often than complete ovarian failure. The X-linked zinc finger gene (ZFX) and diaphanous 2 Drosophila homologue (DIAPH2) are the only candidate genes for ovarian maintenance that map to the X chromosome. Additional, as yet unidentified, genes along the X chromosome must be involved. The search for these genes in humans is hampered by the lack of candidate genes that map to the X chromosome, the scarcity of patients with fortuitous autosomal translocations, and small pedigrees, which hinder mapping of the loci. In addition, difficulties with human germ cell research also make it challenging to dissect genes important to ovarian development. Autosomal genes also are involved in ovarian differentiation and gonadal failure. Follicle-stimulating hormone receptor and ataxia telangiectasia are examples of autosomal genes known to cause human ovarian failure. Transgenic mouse models point to many other candidate autosomal genes, and sequencing of the human homologues in affected women should lead to the discovery of new genes responsible for human ovarian failure. Identification, functional analysis, and mapping of novel genes specifically expressed in the ovary of mice and women eventually should lead to fruitful dissection of essential genes in mammalian ovarian development and maintenance.

Female external genitalia, absent uterus, and probable agonadism in a 46,XY infant with bilateral upper amelia

This report describes a 46,XY phenotypic female infant with absent uterus, probable agonadism, and bilateral upper amelia. The constellation of anomalies is similar to that of the patient described by Temoçin et al. (Acta Paediatr Jpn 1997: 39: 631-633), and may suggest a developmental link between genital region and upper limbs.

Regulation of sexual dimorphism in mammals

Sexual dimorphism in humans has been the subject of wonder for centuries. In 355 BC, Aristotle postulated that sexual dimorphism arose from differences in the heat of semen at the time of copulation. In his scheme, hot semen generated males, whereas cold semen made females (Jacquart, D., and C. Thomasset. Sexuality and Medicine in the Middle Ages, 1988). In medieval times, there was great controversy about the existence of a female pope, who may have in fact had an intersex phenotype (New, M. I., and E. S. Kitzinger. J. Clin. Endocrinol. Metab. 76: 3-13, 1993.). Recent years have seen a resurgence of interest in mechanisms controlling sexual differentiation in mammals. Sex differentiation relies on establishment of chromosomal sex at fertilization, followed by the differentiation of gonads, and ultimately the establishment of phenotypic sex in its final form at puberty. Each event in sex determination depends on the preceding event, and normally, chromosomal, gonadal, and somatic sex all agree. There are, however, instances where chromosomal, gonadal, or somatic sex do not agree, and sexual differentiation is ambiguous, with male and female characteristics combined in a single individual. In humans, well-characterized patients are 46, XY women who have the syndrome of pure gonadal dysgenesis, and a subset of true hermaphrodites are phenotypic men with a 46, XX karyotype. Analysis of such individuals has permitted identification of some of the molecules involved in sex determination, including SRY (sex-determining region Y gene), which is a Y chromosomal gene fulfilling the genetic and conceptual requirements of a testis-determining factor. The purpose of this review is to summarize the molecular basis for syndromes of sexual ambiguity seen in human patients and to identify areas where further research is needed. Understanding how sex-specific gene activity is orchestrated may provide insight into the molecular basis of other cell fate decisions during development which, in turn, may lead to an understanding of aberrant cell fate decisions made in patients with birth defects and during neoplastic change.

A case of ambiguous genitalia with unilateral amelia and unilateral peromelia of the upper limbs

A 7-year-old patient is reported with a 46,XY karyotype, ambiguous genitalia and unilateral amelia and unilateral peromelia of the upper limbs. The external genitalia had essentially a female configuration with labia majora, large clitoris, and narrow vaginal opening. Gonadal tissue was not palpable on either side. The levels of 17-OH progesterone dehydroepiandrosterone sulfate (DHEA-S), androstenedione and luteinizing hormone (LH) were normal, but the level of follicle stimulating hormone (FSH) was elevated minimally. Abdominal ultrasonography (USG) was normal. On pelvic USG, neither uterus nor ovaries were seen. Genitography showed a blind vagina. Gonads, Müllerian and/or Wolffian structures were not observed at laparotomy. Clitoral recession and cut-back vaginoplasty were performed. The occurrence of these findings suggests embryonic testicular regression syndrome with bilateral transverse defect of the upper limbs. The case has been presented because the pattern of the birth defects, including both ambiguous genitalia and unilateral amelia on one side of the upper limbs and unilateral peromelia on the other, have not been described previously.

Agonadism in two sisters with XY gonosomal constitution, mental retardation, short stature, severely retarded bone age, and multiple extragenital malformations: a new autosomal recessive syndrome

We report on 12- and 14-year old sisters with a 46, XY chromosome constitution, normal female external genitalia, and absence of gonadal tissue. Except for omphalocele, right renal agenesis and malrotation of the colon in the elder sister, the internal organs were normal. Both were mentally retarded, of short stature, and had extremely retarded bone age. In addition, they had an almost identical pattern of minor anomalies: peculiar face, hypodontia, short neck, inverted nipples, thoracolumbar scoliosis, "dysplastic" hips, partial clino-/syndactyly of toes. The occurrence of a basically similar set of malformations in two sisters and the first cousin consanguinity of the parents suggests autosomal recessive inheritance. The conserved region of the SRY gene ([high mobility group] HMG box) was sequenced in the elder sib and was normal. No consistent malformations are observed at present in agonadal patients. This supports the idea that several autosomal genes have the potential of influencing the sequence of events of sex determination.

Gonadal agenesis in XX and XY sisters: evidence for the involvement of an autosomal gene

Two agonadic sisters, one with a 46,XY and the other with a 46,XX karyotype, both with normal female external genitalia and hypoplastic Müllerian derivatives, born to a consanguineous marriage, were studied from a clinical, endocrinological, histological, and genetic perspective. Using PCR amplification, Southern hybridization, and DGGE analysis, it was found that the XY patient had no mutations in the conserved sequence of the SRY gene, the putative testis-determining gene in mammals, whereas her XX affected sister is SRY-negative. To our knowledge, this is the first report of XY and XX sibs in familial gonadal agenesis without other somatic abnormalities. The involvement of an autosomal locus impeding gonadal development in both sexes is discussed.

Embryonic testicular regression sequence: a part of the clinical spectrum of 46,XY gonadal dysgenesis

We report on a group of 9 subjects who had a 46,XY karyotype, ambiguous genitalia, abnormalities of sexual duct formation, and lack of gonadal tissue on one or both sides. This is sometimes referred to as "embryonic testicular regression." Previous investigators have suggested that this condition results from loss of testes at a critical stage in development. We examined the possibility that the "embryonic testicular regression" is part of the clinical spectrum of 46,XY gonadal dysgenesis. Four subjects totally lacked gonadal tissue, three of them having ambiguous genitalia, and one a micropenis. The development of incongruous sexual ducts (presence of Müllerian ducts in the subject with micropenis, and absence of Müllerian and Wolffian ducts in two subjects with ambiguous genitalia) suggests that the embryonic gonads were intrinsically functionally abnormal before their disappearance. Five subjects had unilateral gonadal tissue, ambiguous genitalia, and a mix of Wolffian and Müllerian structures. The development of incongruous sexual ducts in 3 of them, the presence of ambiguous external genitalia in 5, and the presence of abnormal gonadal histology in 2 patients all indicate an underlying abnormality of gonadal differentiation in these subjects. The occurrence of testicular regression in several subjects in the family of one patient suggests a genetic basis for the condition. The presence of multiple congenital anomalies in other subjects in our study suggests either a mutation in a single gene that functions in several developmental pathways, or a defect of multiple genes that might be the result of a chromosome deletion.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial occurrence of agonadism and multiple internal malformations in phenotypically normal girls with 46,XY and 46,XX karyotypes, respectively: a new autosomal recessive syndrome

We report on 2 phenotypic sisters, one with 46,XY; the other with 46,XX. The 2 girls had similar related internal malformations, including agonadism, hypoplasia of the right pulmonary artery, hypoplasia of the right lung, isolated dextrocardia with complex vitium cordis, and diaphragmatic hernia (only sib 1) or omphalocele (only sib 2). This combination of malformations did not fit into any of the previously described syndromes. For this syndrome we suggest the acronym PAGOD ([hypoplasia of the] pulmo, and pulmonary artery, agonadism, omphalocele/diaphragmatic defect, dextrocardia). The occurrence of a basically similar set of malformations in 2 unlike sex is interpreted as evidence for autosomal recessive inheritance. The different gonosomal status excludes the Y chromosome as a responsible factor. The peculiar finding of a 46,XX sex chromosome constitution combined with agonadism and an intact urogenitral tract emphasizes the concept of secondary regression of Wolffian and Müllerian structures. The associated malformations of mesodermal structures can be interpreted as midline defects. We suggest that, from the developmental field perspective, secondary regression of midline structures including the gonadal anlage explains the pathogenesis reasonably well.

Gender verification in competitive sports

The possibility that men might masquerade as women and be unfair competitors in women's sports is accepted as outrageous by athletes and the public alike. Since the 1930s, media reports have fuelled claims that individuals who once competed as female athletes subsequently appeared to be men. In most of these cases there was probably ambiguity of the external genitalia, possibly as a result of male pseudohermaphroditism. Nonetheless, beginning at the Rome Olympic Games in 1960, the International Amateur Athletics Federation (IAAF) began establishing rules of eligibility for women athletes. Initially, physical examination was used as a method for gender verification, but this plan was widely resented. Thus, sex chromatin testing (buccal smear) was introduced at the Mexico City Olympic Games in 1968. The principle was that genetic females (46,XX) show a single X-chromatic mass, whereas males (46,XY) do not. Unfortunately, sex chromatin analysis fell out of common diagnostic use by geneticists shortly after the International Olympic Committee (IOC) began its implementation for gender verification. The lack of laboratories routinely performing the test aggravated the problem of errors in interpretation by inexperienced workers, yielding false-positive and false-negative results. However, an even greater problem is that there exist phenotypic females with male sex chromatin patterns (e.g. androgen insensitivity, XY gonadal dysgenesis). These individuals have no athletic advantage as a result of their congenital abnormality and reasonably should not be excluded from competition. That is, only the chromosomal (genetic) sex is analysed by sex chromatin testing, not the anatomical or psychosocial status. For all the above reasons sex chromatin testing unfairly excludes many athletes. Although the IOC offered follow-up physical examinations that could have restored eligibility for those 'failing' sex chromatin tests, most affected athletes seemed to prefer to 'retire'. All these problems remain with the current laboratory based gender verification test, polymerase chain reaction based testing of the SRY gene, the main candidate for male sex determination. Thus, this 'advance' in fact still fails to address the fundamental inequities of laboratory based gender verification tests. The IAAF considered the issue in 1991 and 1992, and concluded that gender verification testing was not needed. This was thought to be especially true because of the current use of urine testing to exclude doping: voiding is observed by an official in order to verify that a sample from a given athlete has actually come from his or her urethra. That males could masquerade as females in these circumstances seems extraordinarily unlikely. Screening for gender is no longer undertaken at IAAF competitions.

Agonadism in a 46,XY patient with CHARGE association

We report on an infant girl born with findings of CHARGE association who proved to be a genetic male (46,XY) on cytogenetic study. Further investigation of the genitalia demonstrated partially female internal organs but absence of gonads by ultrasonography, hormone studies, and absence of ZFY by DNA probe of Yp. Pelvic exploration confirmed lack of gonadal tissue and uterus. Facial phenotype was compatible with CHARGE appearance.

True agonadism: report of a case analyzed with Y-specific DNA probes

We report on a 5-year-old girl with a male karyotype (46,XY), severe psychomotor and physical retardation, minor anomalies, and female external genitalia with a blindly ending vagina. She has normal adrenal function, prepubertal serum gonadotropin and testosterone levels, which did not rise after hCG stimulation. On abdominal exploration no gonads were found, and only mesonephric and Müllerian remnants. She was HY positive, and no deletion was detected in the Y chromosome using 5 different probes. Although a genetic defect is not excluded, pregnancy complications suggest an environmental insult to the developing testes.

Abnormal sexual differentiation and neoplasia

The prevalence of neoplasia is increased in individuals with certain disorders of sexual differentiation. Etiology and frequency of neoplasia vary with the particular disorder. In uncomplicated cryptorchidism, the testis is at least 10 times more likely to undergo neoplastic transformation than a normal scrotal testis. Neoplasia probably is a function of both testicular location (intraabdominal) and underlying dysgenetic structure. If cryptorchidism is unilateral, and if orchiopexy has not been performed prior to age 6-10 years, orchiectomy should be encouraged. In those forms of gonadal dysgenesis not associated with a Y chromosome (e.g., 45,X; 45,X/46,XX; 46,XX) there is no definite increase in neoplasia, suggesting that elevated gonadotropin levels per se are not carcinogenic. Gonadal tumors are found in at least 30% of individuals with XY gonadal dysgenesis and are particularly frequent (55%) in H-Y antigen-positive patients. These tumors are almost always gonadoblastomas or dysgerminomas. Similar tumors are found in 15%-20% of 45,X/46,XY individuals. In either situation the neoplastic transformation could be a) secondary to the existence of XY gonadal tissue in an inhospitable environment, or b) integrally related to that process--genetic or cytogenetic--producing the dysgenetic gonads. The risk of neoplasia is sufficiently high that most of these patients should be offered early gonadal extirpation. The prevalence of gonadal tumors is not increased in Klinefelter's syndrome, further indicating that gonadotropins are not carcinogenic per se. However, Klinefelter patients are 20 times more likely to develop a carcinoma of the breast than are 46,XY males. Extragonadal germ cell tumors also are more common. In female pseudohermaphrodites there is probably no increased risk of neoplasia, whereas, in true hermaphrodites neoplasia is unusual but does occur. Neoplasia occurs in patients with complete testicular feminization (complete androgen insensitivity) but rarely in those with incomplete testicular feminization/Reifenstein's syndrome, 5 alpha-reductase deficiency, anorchia, agonadia, or testosterone biosynthetic defects. In complete testicular feminization the risk of malignant tumors is small prior to age 25. After age 25, it is about 2%-5%. Orchiectomy is recommended after pubertal feminization.

Primary hypogonadism and partial alopecia in three sibs with müllerian hypoplasia in the affected females

We describe 3 sibs, two females and a male, with hypogonadism, defective Müllerian development in the sisters, and partial alopecia consisting of cranial hair only in the center of the scalp. One sister had absent gonads, the other had streak ovaries; both had markedly hypoplastic internal genitalia. Their brother had hormonal and histologic findings consistent with germinal cell aplasia. In view of the fact that the parents were consanguineous, autosomal recessive inheritance of the syndrome is likely.

Testicular regression in a patient with virilized female phenotype

The 16-year old girl studied here had ambiguous external genitalia, ie, enlarged clitoris, pseudo vagina, and rudiments of Wolffian tubes. Her karyotype was 46,XY and she was H-Y antigen-positive. In spite of absence of gonadal tissue, genital virilization suggests presence of testes during embryogenesis. This patient is compared to 20 others with testicular regression from the literature. Autosomal-recessive inheritance of this condition is proposed.

Agonadism with positive H-Y antigen

A 30-year-old phenotypic female was investigated because of absence of the vagina. Her serum gonadotropins were elevated while testosterone was in the normal range for females. Stimulation with human chorionic gonadotropin (hCG) gave no response of testosterone. No uterus, Fallopian tubes, Wolffian derivatives, or the gonads were found at laparotomy. Chromosome analysis showed a 46,XY karyotype. The expression of the H-Y antigen was positive. The results suggest that testicular degeneration in agonadism is not caused by a defective H-Y antigen.

Bilateral adnexal agenesis with an ectopic ovary--case report and review of the literature

Bilateral adnexal agenesis (both ovaries and tubes) is not a common finding. Ectopic ovaries are also very rare. A report of the combination of the two, as far as we know, has never been published. Such a case is presented here with its endocrinological evaluation. The literature concerning these entities is reviewed.

Embryonic testicular regression syndrome: variable phenotypic expression in siblings

Two 46,XY agonadal siblings with variable degrees of sexual ambiguity are described. The eldest child is a phenotypic male with micropenis. The younger patient, a phenotypic female with slight fusion of the genital folds and absent müllerian ducts, conforms to the criteria usually accepted for the diagnosis of true agonadism. Coexistence of anorchia and true agonadism in the same sibship supports the hypothesis, suggested by others, that both disorders are related and are due to the regression of the embryonic testes.

H-Y antigen in Swyer syndrome and the genetics of XY gonadal dysgenesis

The H-Y antigen is a plasma membrane antigen involved in the organogenesis of the mammalian testis. Its expression on human cells is determined by a Y-linked gene. Phenotypic females affected by 46,XY gonadal dysgenesis (Swyer's syndrome) can be either H-Y-positive or H-Y-negative. In this paper we report H-Y antigen and endocrine studies in a sibship with three affected sisters. Immunological studies were performed on two of the patients, and a clearly positive expression was detected in both cases. Endocrine studies consisted in the investigation of the hypothalamic-pituitary-gonadal axis, which revealed that gonadal hormone insufficiency is the only endocrine abnormality associated with the syndrome. A new genetic interpretation and calssification of XY gonadal dysgenesis is proposed.

Male pseudohermaphroditism: genetics and clinical delineation

The genetics and clinical delineation of male pseudohermaphroditism are reviewed. These disorders are categorized initially by their genetic etiology--cytogenetic, Mendelian, or teratogenic. It is especially important to distinguish cytogenetic forms, usually associated with 45,X/46,XY mosaicism, from Mendelian (genetic) forms because in the former the prevalence of gonadoblastomas or dysgerminomas is about 15--20%. Genetic forms include (1) those associated with a multiple malformation pattern, (2) those due to an error in adrenal or testicular hormonal biosynthesis, (3) complete testicular feminization, (4) incomplete testicular feminization, (5) Reifenstein syndrome, (6) pseudovaginal perineoscrotal hypospadias, and (7) agondia, and possibly other conditions. Incomplete testicular feminization and the Reifenstein syndrome may or may not represent varied expressivity of the same trait. The designation pseudovaginal perineoscrotal hypospadias is appropriate only if constellations of clinical features are present and if no metabolic abnormalities are demonstrable. Etiology and available genetic data are reviewed for each of these disorders.

[Pseudohermaphroditism due to XY gonadal absence syndrome (author's transl)]

A case about a 16 year old individual is presented, in whom no internal genitals and vagina were found; no signs of breast development, axillary and pubic hair growth could be detected. The external genitals were hypoplastic. A sinus urogenitalis was present. The sex chromosome pattern was normal male (XY). On both sides of the pelvic wall rudiments of the Fallopian tube were observed by laparoscopy. Testosterone, estradiol, 17 alpha-OH-progesterone as well as androstendione-secretion could not be stimulated by HCG. Basal and LH-RH stimulated gonadotropins indicated a hypergonadotropic state. Height and bodyweight were in the range of a 12-year old boy, the bone age correlated with 14 years.

Diagnosis and management of the infant with genital ambiguity

Clinical management of a child with ambiguous external genitalia requires physicians to consider the immediate management of the condition, as well as parental reactions. They must also obtain the necessary data upon which to make a diagnosis. This review summarizes the most common disorders causing genital ambiguity and suggests approaches toward delineation.

Agonadism: case report and review

A 24-year-old phenotypic girl with primary amenorrhea was referred for further evaluation. The cervix and uterus were absent and no gonadal tissue was present by physical examination or at laparotomy. Her serum FSH was elevated and there was no increase in serum testosterone following HCG stimulation. The defect(s) in this case and similar patients with "agonadism" reported to date are compatible with various genetic hypotheses.

Pseudohermaphroditism due to XY gonadal absence syndrome

A 21-year-old phenotypic female with a 46,XY chromosome complement and gonadal absence was studied. Basal levels of plasma immunoreactive luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, and oestradiol were measured. Pituitary sensitivity and reserve was evaluated by the exogenous administration of synthetic luteinizing hormone-releasing hormone. The episodic release of gonadotrophins was assessed by measuring plasma LH and FSH in plasma samples obtained at 20-minute intervals for a 4-hour period. Endocrine gonadal function was evaluated by a stimulation test with human chorionic gonadotrophin for 3 days. The results showed: a) persistently raised plasma levels of both LH and FSH; b) a pulsatile pattern of release of both gonadotrophins and a normal pituitary response to the synthetic hypothalamic decapeptide; and c) extremely low levels of circulating testosterone and oestradiol with a lack of response to the HCG stimulus. A careful exploratory laparotomy revealed absence of uterus, Fallopian tubes, the Mullerian portion of the vagina, and gonads. No Wolffian derivatives were found. A dissociation of testosterone and the so-called Jost substance effects during early sexual development may explain the findings in this unusual abnormality. The term 'XY gonadal absence syndrome' including five types of variants to designate this condition is proposed.

An XX female with sexual infantilism, absent gonads, and lack of Müllerian ducts

A patient with a 46,XX chromosome constitution showed the following main characteristics: lack of secondary sexual development, female external genitalia with absence of vagina, no gonadal structures, and complete lack of internal genitalia. This is a variant of the gonadal agenesis syndrome so far only described in association with and XY chromosome component. Endrocinology demonstrated that in the absence of gonadal feedback the pituitary responsiveness to synthetic luteinizing hormone-releasing hormone was increased.