A European Network for the Investigation of Gender Incongruence in adolescents.

BACKGROUND: Knowledge regarding the effects and side effects of gender-affirming hormone therapy (GAHT) in adults is rapidly growing, partly through international research networks such as the European Network for the Investigation of Gender Incongruence (ENIGI). However, data on the effects of puberty suppression (PS) and GAHT in transgender and gender diverse (TGD) youth are limited, although these data are of crucial importance, given the controversies surrounding this treatment. AIM: We sought to present a detailed overview of the design of the ENIGI Adolescents study protocol, including the first baseline data. METHODS: The ENIGI Adolescents study is an ongoing multicenter prospective cohort study. This study protocol was developed by 3 European centers that provide endocrine care for TGD adolescents and were already part of the ENIGI collaboration: Amsterdam, Ghent, and Florence. OUTCOMES: Study outcomes include physical effects and side effects, laboratory parameters, bone mineral density, anthropometric characteristics, attitudes toward fertility and fertility preservation, and psychological well-being, which are measured in the study participants during PS and GAHT, up to 3 years after the start of GAHT. RESULTS: Between November 2021 and May 2023, 172 TGD adolescents were included in the ENIGI Adolescents protocol, of whom 51 were assigned male at birth (AMAB) and 121 were assigned female at birth (AFAB); 3 AFAB participants reported a nonbinary gender identification. A total of 76 participants were included at the start of PS, at a median (IQR) age of 13.7 (12.9-16.5) years in AMAB and 13.5 (12.4-16.1) years in AFAB individuals. The remaining 96 participants were included at start of GAHT, at a median (IQR) age of 15.9 (15.1-17.4) years in AFAB and 16.0 (15.1-16.8) years in AMAB individuals. At the time of this report the study was open for inclusion and follow-up measurements were ongoing. CLINICAL IMPLICATIONS: In response to the rising demand for gender-affirming treatment among TGD youth, this ongoing study is fulfilling the need for prospective data on the effects and safety of PS and GAHT, thus providing a foundation for evidence-based healthcare decisions. STRENGTHS AND LIMITATIONS: This study has a strong multicenter, prospective design that allows for systematic data collection. The use of clinical and self-reported data offers a broad range of outcomes to evaluate. Nevertheless, the burden of additional measurements and questionnaires may lead to withdrawal or lower response rates. Few participants with a non-binary gender identity have been included. CONCLUSION: With the ENIGI Adolescents study we aim to create a comprehensive dataset that we can use for a wide range of studies to address current controversies and uncertainties and to improve healthcare for TGD adolescents.

Spleen function is reduced in individuals with NR5A1 variants with or without a difference of sex development: a cross-sectional study.

OBJECTIVE: NR5A1 is a key regulator of sex differentiation and has been implicated in spleen development through transcription activation of TLX1. Concerns exist about hypo- or asplenism in individuals who have a difference of sex development (DSD) due to an NR5A1 disease-causing variant. We aimed to assess spleen anatomy and function in a clinical cohort of such individuals and in their asymptomatic family member carriers. DESIGN: Cross-sectional assessment in 22 patients with a DSD or primary ovarian insufficiency and 5 asymptomatic carriers from 18 families, harboring 14 different NR5A1 variants. METHODS: Spleen anatomy was assessed by ultrasound, spleen function by peripheral blood cell count, white blood cell differentiation, percentage of nonswitched memory B cells, specific pneumococcal antibody response, % pitted red blood cells, and Howell-Jolly bodies. RESULTS: Patients and asymptomatic heterozygous individuals had significantly decreased nonswitched memory B cells compared to healthy controls, but higher than asplenic patients. Thrombocytosis and spleen hypoplasia were present in 50% of heterozygous individuals. Four out of 5 individuals homozygous for the previously described p.(Arg103Gln) variant had asplenia. CONCLUSIONS: Individuals harboring a heterozygous NR5A1 variant that may cause DSD have a considerable risk for functional hyposplenism, irrespective of their gonadal phenotype. Splenic function should be assessed in these individuals, and if affected or unknown, prophylaxis is recommended to prevent invasive encapsulated bacterial infections. The splenic phenotype associated with NR5A1 variants is more severe in homozygous individuals and is, at least for the p.(Arg103Gln) variant, associated with asplenism.

Androgen Excess and Deficiency: Analytical and Diagnostic Approaches.

BACKGROUND: Androgens are synthesized from cholesterol through sequential conversions by enzymes in the adrenal glands and gonads. Serum levels of androgens change during the different phases of life and regulate important developmental and maturational processes. Androgen excess or deficiency can therefore present at various ages in various ways. CONTENT: The diagnostic approach for atypical genitalia, premature pubarche, delayed pubertal onset or progression, and hirsutism or virilization, including measurement of androgens (testosterone, androstenedione, 17-OHprogesterone, dehydroepiandrosterone, and dihydrotestosterone) is discussed in the current review. Androgens can be measured in serum, saliva, urine, or dried blood spots. Techniques to measure androgens, including immunoassays and LC-MS, have their own advantages and pitfalls. In addition, pre- and postanalytical issues are important when measuring androgens. SUMMARY: During clinical interpretation of androgen measurements, it is important to take preanalytical circumstances, such as time of blood withdrawal, into account. As immunoassays have major drawbacks, especially in samples from women and neonates, concentrations measured using these assays should be interpreted with care. Reference intervals can only be used in relation to the measurement technique and the standardization of the assay. In the near future, new androgens will probably be added to the current repertoire to further improve the diagnosis and follow-up of androgen excess or deficiency.

[Children and adolescents with gender questions: dilemmas in the hormonal treatment by multidisciplinary teams]. / Jongeren met genderincongruentie.

In the Netherlands but also in many other countries, there is an increasing social discussion about gender identity and gender diversity, and an increasing number of children and adolescents are seeking medical help because of questions about their gender identity. The cause of this increase is still unknown. Gender questions are diverse and require an individual approach by a multidisciplinary team. A number of adolescents have additional problems such as mood problems, autistiform symptoms and systemic problems. Diagnosis and treatment takes place in accordance with the quality standard for transgender care somatic and psychological. Hormonal treatment can help to reduce gender dysphoria and improve mental health.

Effect of Busulfan and Treosulfan on Gonadal Function after Allogeneic Stem Cell Transplantation in Children and Adolescents with Nonmalignant Diseases Is Not Exposure-Dependent.

With an increasing number of young patients surviving into adulthood after hematopoietic stem cell transplantation (HSCT), gonadal dysfunction becomes an important late effect with significant impact on quality of life. In this retrospective study, we evaluated the exposure of busulfan (Bu) and treosulfan (Treo) in relation to gonadal function in pediatric patients who underwent HSCT for a nonmalignant disease between 1997 and 2018. In the Bu group, 56 patients could be evaluated, and gonadal dysfunction was found in 35 (63%). Lower Bu exposure (ie, cumulative area under the curve [AUC] <70 mg*h/L) was not associated with a reduced risk of gonadal dysfunction (odds ratio [OR], .92; 95% confidence interval [CI], .25 to 3.49; P = .90). In the Treo cohort, 32 patients were evaluable and gonadal insufficiency occurred in 9 patients (28%). Lower Treo exposure (AUC <1750 mg*h/L on day 1) was not associated with a reduced risk of gonadal dysfunction (OR, 1.6; 95% CI, .16 to 36.6; P = .71). Our data do not support the premise that reduced-intensity Bu-based conditioning reduces the risk for gonadal toxicity, and it is unlikely that therapeutic drug monitoring-based reduced treosulfan exposure will further limit the risk of gonadal dysfunction.

Undetectable anti-Mullerian hormone and inhibin B do not preclude the presence of germ cell tumours in 45,X/46,XY or 46,XY gonadal dysgenesis.

OBJECTIVE: Individuals with 45,X/46,XY or 46,XY gonadal dysgenesis are at increased risk of germ cell malignancies. Therefore, prophylactic bilateral gonadectomy is advised in girls and considered in boys with atypical genitalia for undescended, macroscopically abnormal gonads. However, severely dysgenetic gonads may not contain germ cells rendering gonadectomy unnecessary. Therefore, we investigate if undetectable preoperative serum anti-Müllerian hormone (AMH) and inhibin B can predict the absence of germ cells, (pre)malignant or otherwise. DESIGN, PATIENTS AND MEASUREMENTS: Individuals who had undergone bilateral gonadal biopsy and/or gonadectomy because of suspected gonadal dysgenesis in 1999-2019 were included in this retrospective study if preoperative AMH and/or inhibin B were available. Histological material was reviewed by an experienced pathologist. Haematoxylin and eosin and immunohistochemical stainings for SOX9, OCT4, TSPY and SCF (KITL) were used. RESULTS: Thirteen males and 16 females were included, 20 with 46,XY and 9 with 45,X/46,XY DSD. Three females had dysgerminoma alongside gonadoblastoma; two gonadoblastoma, one germ cell neoplasia in situ (GCNIS) and three males had pre-GCNIS and/or pre-gonadoblastoma. Gonadoblastoma and/or dysgerminoma were present in 3/11 individuals with undetectable AMH and inhibin B, one of whom also had non-(pre)malignant germ cells. Of the other 18, in whom AMH and/or inhibin B were detectable, only one had no germ cells. CONCLUSIONS: Undetectable serum AMH and inhibin B cannot reliably predict the absence of germ cells and germ cell tumours in individuals with 45,X/46,XY or 46,XY gonadal dysgenesis. This information should help in counselling about prophylactic gonadectomy, taking into account both the germ cell cancer risk and potential for gonadal function.

Children and adolescents in the Amsterdam Cohort of Gender Dysphoria: trends in diagnostic- and treatment trajectories during the first 20 years of the Dutch Protocol.

BACKGROUND: Twenty years ago, the Dutch Protocol-consisting of a gonadotropin-releasing hormone agonist (GnRHa) to halt puberty and subsequent gender-affirming hormones (GAHs)-was implemented to treat adolescents with gender dysphoria. AIM: To study trends in trajectories in children and adolescents who were referred for evaluation of gender dysphoria and/or treated following the Dutch Protocol. METHODS: The current study is based on a retrospective cohort of 1766 children and adolescents in the Amsterdam Cohort of Gender Dysphoria. OUTCOMES: Outcomes included trends in number of intakes, ratio of assigned sex at birth, age at intake, age at start of GnRHa and GAH, puberty stage at start of GnRHa, proportions of adolescents starting and stopping GnRHa, reasons for refraining from GnRHa, and proportions of people undergoing gender-affirming surgery. RESULTS: A steep increase in referrals was observed over the years. A change in the AMAB:AFAB ratio (assigned male at birth to assigned female at birth) was seen over time, tipping the balance toward AFAB. Age at intake and at start of GnRHa has increased over time. Of possibly eligible adolescents who had their first visit before age 10 years, nearly half started GnRHa vs around two-thirds who had their first visit at or after age 10 years. The proportion starting GnRHa rose only for those first visiting before age 10. Puberty stage at start of GnRHa fluctuated over time. Absence of gender dysphoria diagnosis was the main reason for not starting GnRHa. Very few stopped GnRHa (1.4%), mostly because of remission of gender dysphoria. Age at start of GAH has increased mainly in the most recent years. When a change in law was made in July 2014 no longer requiring gonadectomy to change legal sex, percentages of people undergoing gonadectomy decreased in AMAB and AFAB. CLINICAL IMPLICATIONS: A substantial number of adolescents did not start medical treatment. In the ones who did, risk for retransitioning was very low, providing ongoing support for medical interventions in comprehensively assessed gender diverse adolescents. STRENGTHS AND LIMITATIONS: Important topics on transgender health care for children and adolescents were studied in a large cohort over an unprecedented time span, limited by the retrospective design. CONCLUSION: Trajectories in diagnostic evaluation and medical treatment in children and adolescents referred for gender dysphoria are diverse. Initiating medical treatment and need for surgical procedures depends on not only personal characteristics but societal and legal factors as well.

Prenatal ultrasound finding of atypical genitalia: Counseling, genetic testing and outcomes.

OBJECTIVE: To report uptake of genetic counseling (GC) and prenatal genetic testing after the finding of atypical genitalia on prenatal ultrasound (US) and the clinical and genetic findings of these pregnancies. METHODS: A retrospective cohort study (2017-2019) of atypical fetal genitalia in a large expert center for disorders/differences of sex development. We describe counseling aspects, invasive prenatal testing, genetic and clinical outcome of fetuses apparently without [group 1, n = 22 (38%)] or with [group 2, n = 36 (62%)] additional anomalies on US. RESULTS: In group 1, 86% of parents opted for GC versus 72% in group 2, and respectively 58% and 15% of these parents refrained from invasive testing. Atypical genitalia were postnatally confirmed in 91% (group 1) and 64% (group 2), indicating a high rate of false positive US diagnosis of ambiguous genitalia. Four genetic diagnoses were established in group 1 (18%) and 10 in group 2 (28%). The total genetic diagnostic yield was 24%. No terminations of pregnancy occurred in group 1. CONCLUSIONS: For optimal care, referral for an expert fetal US scan, GC and invasive diagnostics including broad testing should be offered after prenatal detection of isolated atypical genitalia.

Medical decision-making competence regarding puberty suppression: perceptions of transgender adolescents, their parents and clinicians.

According to international transgender care guidelines, transgender adolescents should have medical decision-making competence (MDC) to start puberty suppression (PS) and halt endogenous pubertal development. However, MDC is a debated concept in adolescent transgender care and little is known about the transgender adolescents', their parents', and clinicians' perspectives on this. Increasing our understanding of these perspectives can improve transgender adolescent care. A qualitative interview study with adolescents attending two Dutch gender identity clinics (eight transgender adolescents who proceeded to gender-affirming hormones after PS, and six adolescents who discontinued PS) and 12 of their parents, and focus groups with ten clinicians was conducted. From thematic analysis, three themes emerged regarding transgender adolescents' MDC to start PS: (1) challenges when assessing MDC, (2) aspects that are considered when assessing MDC, and (3) MDC's relevance. The four criteria one needs to fulfill to have MDC-understanding, appreciating, reasoning, communicating a choice-were all, to a greater or lesser extent, mentioned by most participants, just as MDC being relative to a specific decision and context. Interestingly, most adolescents, parents and clinicians find understanding and appreciating PS and its consequences important for MDC. Nevertheless, most state that the adolescents did not fully understand and appreciate PS and its consequences, but were nonetheless able to decide about PS. Parents' support of their child was considered essential in the decision-making process. Clinicians find MDC difficult to assess and put into practice in a uniform way. Dissemination of knowledge about MDC to start PS would help to adequately support adolescents, parents and clinicians in the decision-making process.

Perceptions on the function of puberty suppression of transgender adolescents who continued or discontinued treatment, their parents, and clinicians.

Purpose: Treatment of transgender adolescents with puberty suppression (PS) was developed to provide time for exploration before pursuing gender affirming medical treatment (GAMT) with irreversible effects. It may also result in a more satisfactory physical outcome for those who continue with GAMT. Despite being the current first choice treatment, little research has examined the function of PS from the perspectives of transgender adolescents, their parents, and clinicians. Insight into the perceived functions of PS will help to adequately support adolescents in their decision-making process and give them the care they need. Methods: Qualitative study using interviews with eight transgender adolescents who proceeded with GAMT after PS ("continuers"), six adolescents who discontinued PS ("discontinuers") and 12 parents, and focus groups with ten clinicians. Results: All informants considered inhibition of development of secondary sex characteristics an important function of PS. Most continuers saw PS as the first step of GAMT. Nevertheless, some were glad that the effects were reversible even if they didn't expect to change their minds. Some discontinuers did experience PS as an expanded diagnostic phase. One continuer used the time on PS to get used to living in the affirmed gender role, and several parents found the time helpful to adapt to their child's new gender role. PS provided clinicians more time for diagnostic assessment. Conclusions: Adolescents, parents and clinicians do not all report the same functions of PS. Although international guidelines emphasize providing time for exploration of gender identity as an important reason for PS, many adolescents nowadays seem to have clear ideas about their gender identity and treatment wishes, and experience PS as the first step of GAMT. For some discontinuers however, PS offered a valued period of exploration. Guidelines could be modified to provide more customized care, taking adolescents' and parents' ideas about the functions of PS into account.

Mobile Phone Applications Voice Tools and Voice Pitch Analyzer Validated With LingWAVES to Measure Voice Frequency.

OBJECTIVES: Voice frequency can be measured to assess the voice change in transgender men and women during treatment. There are many applications that can analyze voice frequency. This validation study aimed to compare the ability to measure voice frequency of the mobile phone applications "Voice Tools" and "Voice Pitch Analyzer" with the registration program LingWAVES as the gold standard. STUDY DESIGN: Prospective validation study. METHODS: A total of 45 participants of whom 20 transgender individuals were included. They were asked to read "The North Wind and the Sun" twice. The first measurement compared voice frequency measured by Voice Tools with LingWAVES while the second measurement compared Voice Pitch Analyzer with LingWAVES. The two applications that were being compared simultaneously measured the voice frequency. Pearson's regression correlations were performed to test for correlation between the mobile phone applications and LingWAVES. RESULTS: Significant correlations were demonstrated between the measurements of Voice Tools and LingWAVES (P < 0.001) and between Voice Pitch Analyzer and LingWAVES (P < 0.001). Voice Tools overestimated voice frequency with a median deviation of 2Hz (range -4 to 20). The overestimation was more pronounced in the high ranges. Voice Pitch Analyzer showed underestimation of voice frequency in high ranges. Median deviation was -2Hz (range -16 to 14). CONCLUSIONS: This validation study shows that voice frequency can be reliably measured with the mobile phone applications "Voice Tools" and "Voice Pitch Analyzer". Combined with the ease of use, these applications can be used to measure voice frequency in clinical practice and for research purposes.

We mind your step: understanding and preventing drop-out in the transfer from paediatric to adult tertiary endocrine healthcare.

Introduction: Transition from paediatric to adult endocrinology can be challenging for adolescents, their families and healthcare professionals. Previous studies have shown that up to 25% of young adults with endocrine disorders are lost to follow-up after moving out of paediatric care. This poses a health risk for young adults, which can lead to serious and expensive medical acute and long-term complications. Methods: In order to understand and prevent dropout, we studied electronic medical records of patients with endocrine disorders. These patients were over 15 years old when they attended the paediatric endocrine outpatient clinic (OPC) of our hospital in 2013-2014 and should have made the transfer to adult care at the time of the study. Results: Of 387 adolescents, 131 had an indication for adult follow-up within our university hospital. Thirty-three (25%) were lost to follow-up. In 24 of them (73%), the invitation for the adult OPC had never been sent. We describe the failures in logistic processes that eventually led to dropout in these patients. Conclusion: We found a 25% dropout during transfer from paediatric to adult tertiary endocrine care. Of all dropouts, 73% could be attributed to the failure of logistic steps. In order to prevent these dropouts, we provide practical recommendations for patients and paediatric and adult endocrinologists.

Improved growth with growth hormone treatment in children after hematopoietic stem cell transplantation.

OBJECTIVE: Hematopoietic stem cell transplantation (HSCT) can be a curative treatment for malignant and nonmalignant diseases in children but is associated with significant late effects including growth failure. Growth hormone treatment (GHRx) is offered to improve growth, but limited data are available on its effect on adult height (AH). We aim to evaluate the effectiveness of GHRx. DESIGN: Single-center retrospective study. PATIENTS: Thirty-four patients who had received GHRx for ≥1 year were matched with two controls each, without GHRx, based on sex, indication for HSCT (malignancy, benign haematological disease or immunodeficiency), age at HSCT and conditioning with/without total body irradiation (TBI). All had reached AH. MEASUREMENTS: The primary outcome measure was the difference between AH and predicted AH (PAH) at start of GHRx or the equivalent age in controls (AH-PAH), calculated according to Bailey and Pinneau. RESULTS: GHRx was started at age 12.0 ± 2.6 years; median treatment duration was 3.8 years (range 1.7-9.2). AH-PAH standard deviation score (SDS) was significantly higher in growth hormone (GH) treated boys (-0.5 ± 0.7 SDS) than in controls (-1.5 ± 1.0 SDS, p < .001). Girls also had a higher AH-PAH after GHRx (+0.5 ± 0.6 SDS) compared to controls (-0.2 SDS ±0.7, p < .01). AH remained approximately 2 SDS below target height (TH) in treated and untreated individuals. Among GH-treated children, AH-PAH was higher in those who had received busulfan-based compared to TBI-based conditioning. CONCLUSION: GHRx had a significant positive effect on AH compared to PAH, although AH remained far below TH. Higher AH-PAH was observed in girls and in those conditioned without TBI.

Treatment of congenital adrenal hyperplasia in children aged 0-3 years: a retrospective multicenter analysis of salt supplementation, glucocorticoid and mineralocorticoid medication, growth and blood pressure.

Objectives: International guidelines recommend additional salt supplementation during infancy in classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. The influence of corticoid medication and growth has not been assessed. Aim: To investigate the current use of salt supplementation, fludrocortisone (FC) and hydrocortisone (HC) dosage as well as weight, height, BMI and blood pressure (BP) in CAH children aged 0-3 years. Methods: Retrospective multicentre analysis using data from the I-CAH registry. Salt-treated (ST) and non-salt-treated (NST) children were compared regarding FC and HC dosage, weight, height and BP at 0, 3, 6, 9, 12, 18, 24, 30, and 36 months. Results: We analysed 2483 visits of 331 patients born after year 2000 in 13 countries (male, n = 145) with 203 ST patients (61%). NST children had significantly higher FC dosages at 1.5-4.5 months and higher HC dosages until 1.5 months of age. No differences in weight, length and BP between subgroups were observed. Children of the whole cohort showed increased BMI-SDS during the study period and about half of the reported BP readings were >P95. Conclusion: In children treated with additional salt supplementation, FC and HC dosages are lower during the first months of life but without differences in weight, length and BP until 3 years of age compared to NST children. All children showed an increase in BMI-SDS and a high rate of BP readings >P95 until 3 years, indicating the start of weight gain and negative effects on blood pressure already in very early life.

Optimizing the Timing of Highest Hydrocortisone Dose in Children and Adolescents With 21-Hydroxylase Deficiency.

CONTEXT: Hydrocortisone treatment of young patients with 21-hydroxylase deficiency (21OHD) is given thrice daily, but there is debate about the optimal timing of the highest hydrocortisone dose, either mimicking the physiological diurnal rhythm (morning), or optimally suppressing androgen activity (evening). OBJECTIVE: We aimed to compare 2 standard hydrocortisone timing strategies, either highest dosage in the morning or evening, with respect to hormonal status throughout the day, nocturnal blood pressure (BP), and sleep and activity scores. METHODS: This 6-week crossover study included 39 patients (aged 4-19 years) with 21OHD. Patients were treated for 3 weeks with the highest hydrocortisone dose in the morning, followed by 3 weeks with the highest dose in the evening (n = 21), or vice versa (n = 18). Androstenedione (A4) and 17-hydroxyprogesterone (17OHP) levels were quantified in saliva collected at 5 am; 7 am; 3 pm; and 11 pm during the last 2 days of each treatment period. The main outcome measure was comparison of saliva 17OHP and A4 levels between the 2 treatment strategies. RESULTS: Administration of the highest dose in the evening resulted in significantly lower 17OHP levels at 5 am, whereas the highest dose in the morning resulted in significantly lower 17OHP and A4 levels in the afternoon. The 2 treatment dose regimens were comparable with respect to averaged daily hormone levels, nocturnal BP, and activity and sleep scores. CONCLUSION: No clear benefit for either treatment schedule was established. Given the variation in individual responses, we recommend individually optimizing dose distribution and monitoring disease control at multiple time points.

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.