Growth, puberty and testicular function in boys born small for gestational age with a nonspecific disorder of sex development.

OBJECTIVE: Being born small for gestational age (SGA) is frequently associated with unexplained disorders of sex development (nonspecific DSD) in boys. Little is known about their future growth, puberty and testicular function. Our objective is to determine the long-term endocrine outcome of boys born SGA who have a nonspecific DSD. DESIGN: Boys with a nonspecific DSD born SGA and appropriate for GA (AGA) were retrieved through the International Disorders of Sex Development registry and retrospective data collected, based on a spreadsheet containing 102 items. PATIENTS AND MEASUREMENTS: In total, 179 boys were included, of which 115 were born SGA and 64 were born AGA. Their growth and pubertal development were compared. Serum LH, FSH, testosterone, AMH and inhibin B levels in infancy and puberty were analysed to assess testicular function. RESULTS: At 2 years of age, 30% of SGA boys had incomplete or absent catch-up growth. Boys born SGA also had higher LH during minipuberty and lower testosterone in stimulation tests (p = 0.037 and 0.040, respectively), as compared to boys born AGA. No differences were observed in timing or course of puberty or end-pubertal hormone levels. CONCLUSIONS: Almost one out of three SGA boys with a nonspecific DSD experiences insufficient catch-up growth. In addition, our data suggest dysfunction of infantile Leydig cells or altered regulation of the hypothalamic-pituitary-gonadal axis in SGA boys during childhood. Sex steroid production during puberty seems unaffected.

Testosterone Therapy and Its Monitoring in Adolescent Boys with Hypogonadism: Results of an International Survey from the I-DSD Registry.

It is unclear whether testosterone replacement therapy (TRT) in adolescent boys, affected by a range of endocrine diseases that may be associated with hypogonadism, is particularly common. The aim of this study was to assess the contemporary practice of TRT in boys included in the I-DSD Registry. All participating centres in the I-DSD Registry that had boys between 10 and 18 years of age and with a condition that could be associated with hypogonadism were invited to provide further information in 2019. Information on 162 boys was collected from 15 centres that had a median (range) number of 6 boys per centre (1.35). Of these, 30 (19%) from 9 centres were receiving TRT and the median (range) age at the start was 12.6 years (10.8-16.2), with 6 boys (20%) starting at <12 years. Median (range) age of boys not on TRT was 11.7 years (10.7-17.7), and 69 out of 132 (52%) were <12 years. TRT had been initiated in 20 of 71 (28%) boys with a disorder of gonadal development, 3 of 14 (21%) with a disorder of androgen synthesis, and all 7 (100%) boys with hypogonadotropic hypogonadism. The remainder who did not have TRT included 15 boys with partial androgen insensitivity, 52 with non-specific XY DSD, and 3 with persistent Müllerian duct syndrome. Before starting TRT, liver function and blood count were checked in 19 (68%) and 18 boys (64%), respectively, a bone age assessment was performed in 23 (82%) and bone mineral density assessment in 12 boys (43%). This snapshot of contemporary practice reveals that TRT in boys included in the I-DSD Registry is not very common, whilst the variation in starting and monitoring therapy is quite marked. Standardisation of practice may lead to more effective assessment of treatment outcomes.

X-linked hypophosphataemic rickets in children: clinical phenotype, therapeutic strategies, and molecular background.

INTRODUCTION: X-linked hypophosphataemic rickets (XLHR) is the most common form of hypophosphataemic rickets (HR), which is caused by mutations in the PHEX gene. The aim of this work was to investigate the clinical phenotype, therapeutic strategies, and molecular background of HR in children hospitalised in our clinic. MATERIAL AND METHODS: Eleven patients aged 5.7-18.25 years were included in this study. Molecular analysis was performed using polymerase chain reaction (PCR) and direct sequencing. The PHEX gene was examined in all of the patients, whereas the FGF23 gene was analysed in 5 patients. All of them were treated with alphacalcidol and phosphorus, and 3 were additionally treated with recombinant human growth hormone (rhGH). RESULTS: The mean age at HR diagnosis was 4.05 ± 3.35 years. The mean htSDS was -2.99 ± 1.19. In 2 of the 3 patients treated with rhGH the height gain was +0.4SD and +0.3SD, respectively. In 10 of 11 patients, PHEX gene mutations were found. In 2 children, novel mutations in the PHEX gene were identified: c.325_326dupCA, N110Ifs*7 in one patient and c.899_900delTG, M300Kfs*4 in the remaining one, which coexisted with a known polymorphism c.1769-10C > T, rs3752433. In one patient, a novel deletion of exon 14 and 2 polymorphisms were detected: c.1646-46T > C, g.180417T > C, rs3213493 in intron 15 (known) and g.189156C > T in intron 17 (novel). CONCLUSION: We report 3 novel mutations in the PHEX responsible for HR. Additionally, this study reports the effects of rhGH therapy for growth promotion in HR.

Pathogenic mosaic variants in congenital hypogonadotropic hypogonadism.

PURPOSE: Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder resulting in absent puberty and infertility. The genetic architecture is complex with multiple loci involved, variable expressivity, and incomplete penetrance. The majority of cases are sporadic, consistent with a disease affecting fertility. The current study aims to investigate mosaicism as a genetic mechanism for CHH, focusing on de novo rare variants in CHH genes. METHODS: We evaluated 60 trios for de novo rare sequencing variants (RSV) in known CHH genes using exome sequencing. Potential mosaicism was suspected among RSVs with altered allelic ratios and confirmed using customized ultradeep sequencing (UDS) in multiple tissues. RESULTS: Among the 60 trios, 10 probands harbored de novo pathogenic variants in CHH genes. Custom UDS demonstrated that three of these de novo variants were in fact postzygotic mosaicism-two in FGFR1 (p.Leu630Pro and p.Gly348Arg), and one in CHD7 (p.Arg2428*). Statistically significant variation across multiple tissues (DNA from blood, buccal, hair follicle, urine) confirmed their mosaic nature. CONCLUSIONS: We identified a significant number of de novo pathogenic variants in CHH of which a notable number (3/10) exhibited mosaicism. This report of postzygotic mosaicism in CHH patients provides valuable information for accurate genetic counseling.

Integrating clinical and genetic approaches in the diagnosis of 46,XY disorders of sex development.

46,XY differences and/or disorders of sex development (DSD) are clinically and genetically heterogeneous conditions. Although complete androgen insensitivity syndrome has a strong genotype-phenotype correlation, the other types of 46,XY DSD are less well defined, and thus, the precise diagnosis is challenging. This study focused on comparing the relationship between clinical assessment and genetic findings in a cohort of well-phenotyped patients with 46,XY DSD. The study was an analysis of clinical investigations followed by genetic testing performed on 35 patients presenting to a single center. The clinical assessment included external masculinization score (EMS), endocrine profiling and radiological evaluation. Array-comparative genomic hybridization (array-CGH) and sequencing of DSD-related genes were performed. Using an integrated approach, reaching the definitive diagnosis was possible in 12 children. The correlation between clinical and genetic findings was higher in patients with a more severe phenotype (median EMS 2.5 vs 6; P = 0.04). However, in 13 children, at least one variant of uncertain significance was identified, and most times this variant did not correspond to the original clinical diagnosis. In three patients, the genetic studies guided further clinical assessment which resulted in a reclassification of initial clinical diagnosis. Furthermore, we identified eight patients harboring variants in more than one DSD genes, which was not seen in controls (2.5%; P = 0.0003). In summary, taking into account potential challenges in reaching the definitive diagnosis in 46,XY DSD, only integrated approach seems to be the best routine practice.

Molecular Detection and Incidence of Y Chromosomal Material in Patients with Turner Syndrome.

The presence of a Y chromosome in patients with Turner syndrome (TS) is a risk factor for the development of gonadal tumor and/or virilization. With conventional cytogenetic analysis, some cells containing a Y chromosome can be missed. The aim of this study was to determine the presence and incidence of Y chromosome-derived material in TS patients using PCR and the markers SRY, DYZ1, DYZ3, DYS132, ZFY, and TSPY. Fifty-five TS patients (aged 5.5-26.75 years) were analyzed. A total of 17/55 (30.9%) were Y-positive, but only 7/17 had a Y chromosome in their karyotype and underwent gonadectomy. In 2 of these patients (28.6%), histopathologic examination revealed gonadoblastoma and dysgerminoma, respectively. In 8 patients in the studied group (8/55; 14.5%), the TSPY gene was detected, and the SRY gene (or a fragment) was identified in 9(3)/55 patients. No coding region mutations were observed in these SRY-positive patients. In conclusion, we have shown a high prevalence of Y chromosomal material in TS. Y markers were also observed in patients who had no Y chromosome in their karyotype, and PCR is very precise in detecting the presence of genetic material from the Y chromosome. Further follow-up of these Y-positive TS patients is mandatory.

[Y chromosome in Turner syndrome]. / Chromosom Y w zespole Turnera.

Turner syndrome (TS) is an inherited genetic disorder caused by numerical and/or structural chromosome X aberrations occurring at a frequency of 1:1200-1:2500 live-born girls. The most common karyotype is X chromosome monosomy (45,X) (approximately 50-60% of cases). Approximately 5-6% of patients may have abnormal Y chromosome or mosaicism characterized by the coexistence of 45,X cell line with cell line in which all or part of chromosome Y is present. In patients with TS who have all or fragmented genetic material from chromosome Y there is a substantial risk of cancerous lesions in these dysgenetic gonads. This paper stands for the review of the current knowledge on the genetic material of the Y chromosome in TS, especially in view of the risk of developing malignancies such as gonadoblastoma and dysgerminoma.

Changes over time in sex assignment for disorders of sex development.

BACKGROUND AND OBJECTIVE: It is unclear whether the proportion of infants with a disorder of sex development who are raised as male or female has changed over time. The temporal trends in sex assignment of affected cases entered in the International Disorder of Sex Development (I-DSD) Registry were studied. METHODS: Cases of disorders of sex development reported as partial androgen insensitivity syndrome (PAIS; n = 118), disorder of gonadal development (DGD; n = 232), and disorder of androgen synthesis (DAS; n = 104) were divided into those who were born before 1990, 1990-1999, and after 1999. External appearance of the genitalia was described by the external masculinization score. RESULTS: The median (5th-95th percentile) external masculinization scores of those infants with PAIS, DGD, and DAS who were raised as boys were 6 (2-9), 6 (3-9), and 6 (1-12), respectively, and were significantly higher than in those raised as girls (2 [0-6], 2 [0-7], and 0 [0-5], respectively); this difference was maintained in the 3 temporal birth cohorts (P < .01). Of the 118 cases in the pre-1990 cohort, 41 (35%) were raised as boys; of the 148 cases in the 1990-1999 cohort, 60 (41%) were raised as boys; and of the 188 cases in the post-1999 cohort, 128 (68%) were raised as boys. CONCLUSIONS: Although there is an association between the external appearance of the genitalia and the choice of sex assignment, there are clear temporal trends in this practice pointing toward an increased likelihood of affected infants being raised as boys. The impact of this change in practice on long-term health outcomes requires additional focus.