Pathogenesis of germ cell neoplasia in testicular dysgenesis and disorders of sex development.

Development of human gonads is a sex-dimorphic process which evolved to produce sex-specific types of germ cells. The process of gonadal sex differentiation is directed by the action of the somatic cells and ultimately results in germ cells differentiating to become functional gametes through spermatogenesis or oogenesis. This tightly controlled process depends on the proper sequential expression of many genes and signalling pathways. Disturbances of this process can be manifested as a large spectrum of disorders, ranging from severe disorders of sex development (DSD) to - in the genetic male - mild reproductive problems within the testicular dysgenesis syndrome (TDS), with large overlap between the syndromes. These disorders carry an increased but variable risk of germ cell neoplasia. In this review, we discuss the pathogenesis of germ cell neoplasia associated with gonadal dysgenesis, especially in individuals with 46,XY DSD. We summarise knowledge concerning development and sex differentiation of human gonads, with focus on sex-dimorphic steps of germ cell maturation, including meiosis. We also briefly outline the histopathology of germ cell neoplasia in situ (GCNIS) and gonadoblastoma (GDB), which are essentially the same precursor lesion but with different morphological structure dependent upon the masculinisation of the somatic niche. To assess the risk of germ cell neoplasia in different types of DSD, we have performed a PubMed search and provide here a synthesis of the evidence from studies published since 2006. We present a model for pathogenesis of GCNIS/GDB in TDS/DSD, with the risk of malignancy determined by the presence of the testis-inducing Y chromosome and the degree of masculinisation. The associations between phenotype and the risk of neoplasia are likely further modulated in each individual by the constellation of the gene polymorphisms and environmental factors.

Pubertal Progression and Reproductive Hormones in Healthy Girls With Transient Thelarche.

Context: Detailed evaluation of pubertal progression in girls from longitudinal studies is sparse, and the phenomenon of transient thelarche (TT), defined as the appearance, regression, and subsequent reappearance of breast buds, in healthy girls remains undescribed. Objective: To describe TT in terms of pubertal progression, growth, genotypes, and reproductive hormones and to apply new puberty nomograms for breast stages, pubic hair, and menarche. Design: A prospective, longitudinal population-based study. Patients or Other Participants: Ninety-eight healthy Danish schoolchildren (Caucasian girls) followed longitudinally as part of the COPENHAGEN Puberty Study were included in the evaluation of TT. A total of 1466 girls from 2 cross-sectional studies were included in the creation of the puberty nomograms. Intervention(s): None. Main Outcome Measure(s): Pubertal progression, specifically thelarche, reproductive hormones, genotype, and growth. Results: Twelve of 98 (12%) girls experienced TT. A larger proportion of girls with TT entered puberty by the pubarche pathway (50%) compared with girls with normal progression (15.4%), P = 0.014. Girls with TT progressed through puberty normally when evaluated using puberty nomograms. Reproductive hormones and growth velocity were lower at the first (transient) thelarche than the second (permanent) thelarche. Conclusion: TT is a frequent phenomenon that appears to be a peripheral occurrence independent of central puberty. It does not appear to affect subsequent pubertal progression as evaluated by our new puberty nomograms.

Pubertal development in healthy children is mirrored by DNA methylation patterns in peripheral blood.

Puberty marks numerous physiological processes which are initiated by central activation of the hypothalamic-pituitary-gonadal axis, followed by development of secondary sexual characteristics. To a large extent, pubertal timing is heritable, but current knowledge of genetic polymorphisms only explains few months in the large inter-individual variation in the timing of puberty. We have analysed longitudinal genome-wide changes in DNA methylation in peripheral blood samples (n = 102) obtained from 51 healthy children before and after pubertal onset. We show that changes in single methylation sites are tightly associated with physiological pubertal transition and altered reproductive hormone levels. These methylation sites cluster in and around genes enriched for biological functions related to pubertal development. Importantly, we identified that methylation of the genomic region containing the promoter of TRIP6 was co-ordinately regulated as a function of pubertal development. In accordance, immunohistochemistry identified TRIP6 in adult, but not pre-pubertal, testicular Leydig cells and circulating TRIP6 levels doubled during puberty. Using elastic net prediction models, methylation patterns predicted pubertal development more accurately than chronological age. We demonstrate for the first time that pubertal attainment of secondary sexual characteristics is mirrored by changes in DNA methylation patterns in peripheral blood. Thus, modulations of the epigenome seem involved in regulation of the individual pubertal timing.

Anti-müllerian hormone and its clinical use in pediatrics with special emphasis on disorders of sex development.

Using measurements of circulating anti-Müllerian hormone (AMH) in diagnosing and managing reproductive disorders in pediatric patients requires thorough knowledge on normative values according to age and gender. We provide age- and sex-specific reference ranges for the Immunotech assay and conversion factors for the DSL and Generation II assays. With this tool in hand, the pediatrician can use serum concentrations of AMH when determining the presence of testicular tissue in patients with bilaterally absent testes or more severe Disorders of Sex Development (DSD). Furthermore, AMH can be used as a marker of premature ovarian insufficiency (POI) in both Turner Syndrome patients and in girls with cancer after treatment with alkylating gonadotoxic agents. Lastly, its usefulness has been proposed in the diagnosis of polycystic ovarian syndrome (PCOS) and ovarian granulosa cell tumors and in the evaluation of patients with hypogonadotropic hypogonadism.

45,X/46,XY mosaicism: phenotypic characteristics, growth, and reproductive function--a retrospective longitudinal study.

CONTEXT: Most previous studies of 45,X/46,XY mosaicism are case reports or have described single aspects of the disease. OBJECTIVE: The objective was to provide longitudinal data of patients with 45,X/46,XY mosaicism. DESIGN: This was a retrospective, longitudinal study conducted from June 1990 to January 2012. SETTING: The study took place at a tertiary pediatric and andrological referral center. PATIENTS OR OTHER PARTICIPANTS: Twenty-five patients (18 boys, seven girls) with 45,X/46,XY mosaicism and its variants were included and were compared to healthy controls. INTERVENTION(S): No interventions were included in the study. MAIN OUTCOME MEASURE(S): Phenotypes were scored using external masculinization scores. Serum LH, FSH, testosterone, estradiol, and inhibin B levels were reported in male patients. IGF-I levels and height were reported in all patients. Available biopsies/gonadectomies were histologically examined. RESULTS: Fourteen of 18 males had external masculinization scores consistent with normal virilization. Ten of 11 male patients experienced spontaneous puberty. Median height sd score was -2.0 (range, -3 to 0.3) for males and -2.2 (range, -2.5 to -1.4) for females, both considerably below genetic potential. Median 1-yr height gain after GH treatment in seven patients was 0.5 sd (0.1 to 1.2). All tissue samples from 15 patients (eight males, seven females) revealed abnormal gonadal histology. Four patients had carcinoma in situ (CIS); two had tissue samples available from early childhood, one showing CIS. CONCLUSIONS: Gonadal function in most 45,X/46,XY males, even those with genital ambiguity, seems sufficient for spontaneous puberty. Short stature and 45,X/46,XY mosaicism seem associated, but patients appear to benefit from GH treatment. Histology from two patients with biopsies from early childhood indicates that CIS originates before puberty.