Laboratory Changes During Gender-Affirming Hormone Therapy in Transgender Adolescents

OBJECTIVES

Guidelines for monitoring of medications frequently used in the gender-affirming care of transgender and gender-diverse (TGD) adolescents are based on studies in adults or other medical conditions. In this study, we aimed to investigate commonly screened laboratory measurements in TGD adolescents receiving gender-affirming hormone therapy (GAHT).

METHODS

TGD adolescents were recruited from 4 study sites in the United States before beginning GAHT. Hemoglobin, hematocrit, hemoglobin A1c, alanine transaminase, aspartate aminotransferase, prolactin, and potassium were abstracted from the medical record at baseline and at 6, 12, and 24 months after starting GAHT.

RESULTS

Two-hundred and ninety-three participants (68% designated female at birth) with no previous history of gonadotropin-releasing hormone analog use were included in the analysis. Hemoglobin and hematocrit decreased in adolescents prescribed estradiol (-1.4 mg/dL and -3.6%, respectively) and increased in adolescents prescribed testosterone (+1.0 mg/dL and +3.9%) by 6 months after GAHT initiation. Thirteen (6.5%) participants prescribed testosterone had hematocrit > 50% during GAHT. There were no differences in hemoglobin A1c, alanine transaminase, or aspartate aminotransferase. There was a small increase in prolactin after 6 months of estradiol therapy in transfeminine adolescents. Hyperkalemia in transfeminine adolescents taking spironolactone was infrequent and transient if present.

CONCLUSIONS

Abnormal laboratory results are rare in TGD adolescents prescribed GAHT and, if present, occur within 6 months of GAHT initiation. Future guidelines may not require routine screening of these laboratory parameters beyond 6 months of GAHT in otherwise healthy TGD adolescents.

Mental Health and Gender Affirmation of Black and Latine Transgender/Nonbinary Youth Compared to White Peers Prior to Hormone Initiation

PURPOSE

To compare baseline mental health symptoms and gender affirmation between Black/Latine versus White transgender/nonbinary youth (BLTY vs. WTY) and examine relationships between gender affirmation and mental health symptoms, and whether associations differed by race/ethnicity subgroup.

METHODS

Baseline data were analyzed from the gender-affirming hormone cohort of the Trans Youth Care United States Study-a 4-clinic site, observational study. Mental health symptoms assessed included depression, suicidality, and anxiety. Gender affirmation measures included the parental acceptance subscale from the perceived Parental Attitudes of Gender Expansiveness Scale-Youth Report; non-affirmation, internalized transphobia, and community connectedness subscales from the Gender Minority Stress and Resilience Measure-Adolescent; and self-reported living full time in affirmed gender. Fisher exact tests and independent sample t tests compared mental health symptoms and gender affirmation between subgroups. Logistic regression analyses evaluated associations between gender affirmation and mental health symptoms. Interaction analyses assessed differences in associations between subgroups.

RESULTS

The sample (mean age 16 years, range 12-20 years) included 92 BLTY (35%) and 170 WTY (65%). Subgroups had comparable prevalence of depression and anxiety symptoms. WTY had higher prevalence of lifetime suicidality (73% vs. 59%; p = .02). There were no differences in gender affirmation. Among the whole sample, higher parental acceptance decreased odds of depression symptoms. Not living in affirmed gender increased odds of depression symptoms. Higher non-affirmation and internalized transphobia increased odds of depression and anxiety symptoms and suicidality. Associations did not vary by subgroup.

DISCUSSION

BLTY and WTY had comparable mental health symptoms. For both subgroups, gender affirmation decreased odds of those symptoms.

High Internalized Transphobia and Low Gender Identity Pride Are Associated With Depression Symptoms Among Transgender and Gender-Diverse Youth

PURPOSE

Prior studies have identified a significant relationship between internalized transphobia and poor mental health among transgender and gender-diverse (TGD) adults; however, this relationship has not been extensively examined among youth. Further, little research has sought to explore protective factors, such as identity pride, and their influence on this relationship. We examined the association between internalized transphobia and depression and anxiety symptoms among TGD youth and explored the moderating role of gender identity pride on these associations.

METHODS

Participants were 315 TGD youth ages 12-20 years (mean = 16; standard deviation = 1.89) seeking gender-affirming hormone treatment at one of four major pediatric hospitals across the United States. At the time of enrollment, participants were naïve to gender-affirming hormone treatment. Participants self-reported mental health, internalized transphobia, and identity pride. Multiple regression models were used with depression and anxiety symptoms as outcomes and age, designated sex at birth, and perceived parental support included as covariates.

RESULTS

Greater internalized transphobia was associated with greater depressive symptoms, and gender identity pride moderated this relationship, such that greater gender identity pride was associated with fewer depressive symptoms. Greater internalized transphobia was significantly associated with greater anxiety symptoms; no moderation effect was observed for this relationship.

DISCUSSION

Gender identity pride influenced mental health symptoms for youth experiencing internalized transphobia and represents a potential key protective factor. These results support efforts to further develop, test, and implement clinical inventions to bolster identity pride for TGD youth.

Gender-Affirming Care of Transgender and Gender-Diverse Youth: Current Concepts

Increasing numbers of transgender and gender-diverse (TGD) youth, from early puberty through late adolescence, are seeking medical services to bring their physical sex characteristics into alignment with their gender identity-their inner sense of self as male or female or elsewhere on the gender spectrum. Numerous studies, primarily of short- and medium-term duration (up to 6 years), demonstrate the clearly beneficial-even lifesaving-mental health impact of gender-affirming medical care in TGD youth. However, there are significant gaps in knowledge and challenges to such care. Long-term safety and efficacy studies are needed to optimize medical care for TGD youth.

Psychosocial Functioning in Transgender Youth after 2 Years of Hormones

BACKGROUND

Limited prospective outcome data exist regarding transgender and nonbinary youth receiving gender-affirming hormones (GAH; testosterone or estradiol).

METHODS

We characterized the longitudinal course of psychosocial functioning during the 2 years after GAH initiation in a prospective cohort of transgender and nonbinary youth in the United States. Participants were enrolled in a four-site prospective, observational study of physical and psychosocial outcomes. Participants completed the Transgender Congruence Scale, the Beck Depression Inventory-II, the Revised Children's Manifest Anxiety Scale (Second Edition), and the Positive Affect and Life Satisfaction measures from the NIH (National Institutes of Health) Toolbox Emotion Battery at baseline and at 6, 12, 18, and 24 months after GAH initiation. We used latent growth curve modeling to examine individual trajectories of appearance congruence, depression, anxiety, positive affect, and life satisfaction over a period of 2 years. We also examined how initial levels of and rates of change in appearance congruence correlated with those of each psychosocial outcome.

RESULTS

A total of 315 transgender and nonbinary participants 12 to 20 years of age (mean [±SD], 16±1.9) were enrolled in the study. A total of 190 participants (60.3%) were transmasculine (i.e., persons designated female at birth who identify along the masculine spectrum), 185 (58.7%) were non-Latinx or non-Latine White, and 25 (7.9%) had received previous pubertal suppression treatment. During the study period, appearance congruence, positive affect, and life satisfaction increased, and depression and anxiety symptoms decreased. Increases in appearance congruence were associated with concurrent increases in positive affect and life satisfaction and decreases in depression and anxiety symptoms. The most common adverse event was suicidal ideation (in 11 participants [3.5%]); death by suicide occurred in 2 participants.

CONCLUSIONS

In this 2-year study involving transgender and nonbinary youth, GAH improved appearance congruence and psychosocial functioning. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.).

The Evolution of Adolescent Gender-Affirming Care: An Historical Perspective

While individuals have demonstrated gender diversity throughout history, the use of medication and/or surgery to bring a person's physical sex characteristics into alignment with their gender identity is relatively recent, with origins in the first half of the 20th century. Adolescent gender-affirming care, however, did not emerge until the late 20th century and has been built upon pioneering work from the Netherlands, first published in 1998. Since that time, evolving protocols for gender-diverse adolescents have been incorporated into clinical practice guidelines and standards of care published by the Endocrine Society and World Professional Association for Transgender Health, respectively, and have been endorsed by major medical and mental health professional societies around the world. In addition, in recent decades, evidence has continued to emerge supporting the concept that gender identity is not simply a psychosocial construct but likely reflects a complex interplay of biological, environmental, and cultural factors. Notably, however, while there has been increased acceptance of gender diversity in some parts of the world, transgender adolescents and those who provide them with gender-affirming medical care, particularly in the USA, have been caught in the crosshairs of a culture war, with the risk of preventing access to care that published studies have indicated may be lifesaving. Despite such challenges and barriers to care, currently available evidence supports the benefits of an interdisciplinary model of gender-affirming medical care for transgender/gender-diverse adolescents. Further long-term safety and efficacy studies are needed to optimize such care.

Standards of Care for the Health of Transgender and Gender Diverse People, Version 8

Background: Transgender healthcare is a rapidly evolving interdisciplinary field. In the last decade, there has been an unprecedented increase in the number and visibility of transgender and gender diverse (TGD) people seeking support and gender-affirming medical treatment in parallel with a significant rise in the scientific literature in this area. The World Professional Association for Transgender Health (WPATH) is an international, multidisciplinary, professional association whose mission is to promote evidence-based care, education, research, public policy, and respect in transgender health. One of the main functions of WPATH is to promote the highest standards of health care for TGD people through the Standards of Care (SOC). The SOC was initially developed in 1979 and the last version (SOC-7) was published in 2012. In view of the increasing scientific evidence, WPATH commissioned a new version of the Standards of Care, the SOC-8. Aim: The overall goal of SOC-8 is to provide health care professionals (HCPs) with clinical guidance to assist TGD people in accessing safe and effective pathways to achieving lasting personal comfort with their gendered selves with the aim of optimizing their overall physical health, psychological well-being, and self-fulfillment. Methods: The SOC-8 is based on the best available science and expert professional consensus in transgender health. International professionals and stakeholders were selected to serve on the SOC-8 committee. Recommendation statements were developed based on data derived from independent systematic literature reviews, where available, background reviews and expert opinions. Grading of recommendations was based on the available evidence supporting interventions, a discussion of risks and harms, as well as the feasibility and acceptability within different contexts and country settings. Results: A total of 18 chapters were developed as part of the SOC-8. They contain recommendations for health care professionals who provide care and treatment for TGD people. Each of the recommendations is followed by explanatory text with relevant references. General areas related to transgender health are covered in the chapters Terminology, Global Applicability, Population Estimates, and Education. The chapters developed for the diverse population of TGD people include Assessment of Adults, Adolescents, Children, Nonbinary, Eunuchs, and Intersex Individuals, and people living in Institutional Environments. Finally, the chapters related to gender-affirming treatment are Hormone Therapy, Surgery and Postoperative Care, Voice and Communication, Primary Care, Reproductive Health, Sexual Health, and Mental Health. Conclusions: The SOC-8 guidelines are intended to be flexible to meet the diverse health care needs of TGD people globally. While adaptable, they offer standards for promoting optimal health care and guidance for the treatment of people experiencing gender incongruence. As in all previous versions of the SOC, the criteria set forth in this document for gender-affirming medical interventions are clinical guidelines; individual health care professionals and programs may modify these in consultation with the TGD person.

The effect of gender-affirming hormone treatment on serum creatinine in transgender and gender-diverse youth: implications for estimating GFR

BACKGROUND

Equations for estimated glomerular filtration rate (eGFR) based on serum creatinine include terms for sex/gender. For transgender and gender-diverse (TGD) youth, gender-affirming hormone (GAH) treatment may affect serum creatinine and in turn eGFR.

METHODS

TGD youth were recruited for this prospective, longitudinal, observational study prior to starting GAH treatment. Data collected as part of routine clinical care were abstracted from the medical record.

RESULTS

For participants designated male at birth (DMAB, N = 92), serum creatinine decreased within 6 months of estradiol treatment (mean ± SD 0.83 ± 0.12 mg/dL to 0.76 ± 0.12 mg/dL, p < 0.001); for participants designated female at birth (DFAB, n = 194), serum creatinine increased within 6 months of testosterone treatment (0.68 ± 0.10 mg/dL to 0.79 ± 0.11 mg/dL, p < 0.001). Participants DFAB treated with testosterone had serum creatinine similar to that of participants DMAB at baseline, whereas even after estradiol treatment, serum creatinine in participants DMAB remained higher than that of participants DFAB at baseline. Compared to reference groups drawn from the National Health and Nutritional Examination Survey, serum creatinine after 12 months of GAH was more similar when compared by gender identity than by designated sex.

CONCLUSION

GAH treatment leads to changes in serum creatinine within 6 months of treatment. Clinicians should consider a patient's hormonal exposure when estimating kidney function via eGFR and use other methods to estimate GFR if eGFR based on serum creatinine is concerning.

Growth in Transgender/Gender-Diverse Youth in the First Year of Treatment With Gonadotropin-Releasing Hormone Agonists

PURPOSE

Transgender/gender-diverse (TGD) youth are treated with gonadotropin-releasing hormone agonists (GnRHas) to halt endogenous puberty and prevent the development of secondary sex characteristics discordant with their gender identity. This treatment may have significant impact on growth and height velocity (HV).

METHODS

Participants were recruited prior to GnRHa initiation from four gender specialty clinics in the U.S. Anthropometric, laboratory, and Tanner-stage data were abstracted from medical records.

RESULTS

Fifty-five TGD youth (47% designated male at birth) with a mean ± standard deviation age of 11.5 ± 1.2 years were included in the analysis. HV in the first year of GnRHa use was median (interquartile range) 5.1 (3.7-5.6) cm/year. Later Tanner stage at GnRHa initiation was associated with lower HV: 5.3 (4.4-5.6) cm/year for Tanner stage II, 4.4 (3.3-6.0) cm/year for Tanner stage III, and 1.6 (1.5-2.9) cm/year for Tanner stage IV (p = .001). When controlled for age, there was not a significant difference in mean HV between TGD youth and prepubertal youth; however, when stratified by Tanner stage individuals starting GnRHa at Tanner stage IV had an HV below that of prepubertal youth, 1.6 (1.5-2.9) versus 6.1 (4.3-6.5) cm/year, p = .006.

CONCLUSIONS

Overall, TGD youth treated with GnRHa have HV similar to that of prepubertal children, but TGD youth who start GnRHa later in puberty have an HV below the prepubertal range. Ongoing follow-up of this cohort will determine the impact of GnRHa treatment on adult height.

Increasing Access to Care for Transgender/Gender Diverse Youth Using Telehealth: A Quality Improvement Project

Purpose: We sought to expand telehealth at an academic multidisciplinary pediatric gender center to increase access to gender-affirming care without compromising communication, privacy, or patient satisfaction. Materials and Methods: Patient needs assessments were performed from January 2019 to March 2020. The severe acute respiratory syndrome coronavirus 2 pandemic accelerated implementation of the quality improvement project, and clinically appropriate patients were scheduled for video visits starting March 16, 2020. From September 8, 2020 to October 2, 2020, caregivers of transgender and gender diverse (TGD) minors or TGD young adults pursuing gender-affirming medications completed 9-item surveys evaluating communication quality and privacy, access to care, and quality of services for video and clinic visits. Answers were rated via Likert scales (1 = strongly agree, 5 = strongly disagree; 1 = less travel time, 4 = more travel time). Results: Needs assessment (n = 69) showed that 63.8% felt that video visits would improve follow-up. Survey participants (n = 91) reported statistically significant differences (p < 0.05) in several areas. Compared with clinic visits, video visits were more convenient, 1.21 ± 0.435 versus 2.36 ± 1.207, took less time from other activities, 4.55 ± 0.522 versus 2.93 ± 1.281, required less travel time, 1.03 ± 0.180 versus 2.63 ± 0.901, and were more acceptable, 1.35 ± 0.545 versus 1.65 ± 0.736. Participants were more likely to choose video visits in the future, 1.32 ± 0.555 versus 1.57 ± 0.732. There were no statistically significant differences in communication quality, privacy, or overall satisfaction. Conclusion: An integrated clinic-video visit model increases access to gender-affirming care for TGD youth while maintaining excellent communication, privacy, and patient satisfaction.

Challenges in the care of transgender and gender-diverse youth: an endocrinologist's view

An increasing number of transgender and gender-diverse (TGD) youth (early pubertal through to late adolescent, typically 9-10 through to 18 years of age) are seeking medical services to bring their physical sex characteristics into alignment with their gender identity - their inner sense of self as male or female or somewhere on the gender spectrum. Compelling research has demonstrated the clear mental health - even life-saving - benefits of gender-affirming care, but current clinical practice guidelines and standards of care are based on only several short-term and a few medium-term outcomes studies complemented by expert opinion. Nevertheless, although the relative paucity of outcomes data raises concerns, the stance of not intervening until more is known is not a neutral option, and large observational studies evaluating current models of care are necessary and are now underway. This Review highlights key advances in our understanding of transgender and gender-diverse youth, the challenges of providing gender-affirming care, gaps in knowledge and priorities for research.

Association of High-Density Lipoprotein Cholesterol With Sex Steroid Treatment in Transgender and Gender-Diverse Youth

This cohort study analyzes the association of sex steroids with cholesterol in different sex-chromosome contexts.

Histrelin Implants for Suppression of Puberty in Youth with Gender Dysphoria: A Comparison of 50 mcg/Day (Vantas) and 65 mcg/Day (SupprelinLA)

Purpose: Development of incongruent secondary sex characteristics in transgender youth can intensify or trigger the onset of gender dysphoria. Guidelines from professional organizations recommend gonadotropin-releasing hormone agonists, including histrelin implants (Vantas and SupprelinLA) to suppress endogenous puberty. Although Vantas does not have a pediatric indication, it is anecdotally being used in pediatric gender centers throughout the United States because of its substantially lower cost. This retrospective study aimed to determine if both implants were effective in suppressing the hypothalamic-pituitary-gonadal axis in early-to-mid pubertal youth with gender dysphoria. Methods: Youth with gender dysphoria receiving care at the Center for Transyouth Health and Development at Children's Hospital Los Angeles (CHLA) or participants from an ongoing observational trial with a histrelin implant placed for pubertal suppression at Tanner stage 2 or 3 were included. Sex steroid (testosterone or estradiol) and gonadotropin measurements at baseline (T0) and then 2 to 12 months following implant placement (T1) were abstracted from medical records. Results: Of the 66 eligible participants, 52% were designated female at birth. Most participants were white (60.6%). Twenty participants (30.3%) had a Vantas implant and 46 (69.7%) had a SupprelinLA implant. Mean age of insertion was 11.3 years. Gonadotropin and sex steroid levels were significantly decreased at T1 (2-12 months after insertion of implant), with no differences between implants. Conclusion: These results indicate that both implants are effective in suppressing puberty in early-to-mid pubertal youth with gender dysphoria. These data may inform decisions about insurance coverage of Supprelin and/or Vantas for youth with gender dysphoria.

Consensus Parameter: Research Methodologies to Evaluate Neurodevelopmental Effects of Pubertal Suppression in Transgender Youth

Purpose: Pubertal suppression is standard of care for early pubertal transgender youth to prevent the development of undesired and distressing secondary sex characteristics incongruent with gender identity. Preliminary evidence suggests pubertal suppression improves mental health functioning. Given the widespread changes in brain and cognition that occur during puberty, a critical question is whether this treatment impacts neurodevelopment.

Methods: A Delphi consensus procedure engaged 24 international experts in neurodevelopment, gender development, puberty/adolescence, neuroendocrinology, and statistics/psychometrics to identify priority research methodologies to address the empirical question: is pubertal suppression treatment associated with real-world neurocognitive sequelae? Recommended study approaches reaching 80% consensus were included in the consensus parameter.

Results: The Delphi procedure identified 160 initial expert recommendations, 44 of which ultimately achieved consensus. Consensus study design elements include the following: a minimum of three measurement time points, pubertal staging at baseline, statistical modeling of sex in analyses, use of analytic approaches that account for heterogeneity, and use of multiple comparison groups to minimize the limitations of any one group. Consensus study comparison groups include untreated transgender youth matched on pubertal stage, cisgender (i.e., gender congruent) youth matched on pubertal stage, and an independent sample from a large-scale youth development database. The consensus domains for assessment includes: mental health, executive function/cognitive control, and social awareness/functioning.

Conclusion: An international interdisciplinary team of experts achieved consensus around primary methods and domains for assessing neurodevelopmental effects (i.e., benefits and/or difficulties) of pubertal suppression treatment in transgender youth.

Physiological and Metabolic Characteristics of a Cohort of Transgender and Gender-Diverse Youth in the United States

PURPOSE

The purpose of this study was to describe baseline physical and laboratory characteristics of participants in the largest prospective study of transgender and gender-diverse (TGD) youth in the United States.

METHODS

Participants were recruited from four clinics which specialize in the care of TGD youth before starting either GnRH analogs for pubertal suppression or gender-affirming hormone treatment. Anthropometric and laboratory measurements were abstracted from the medical chart. Baseline characteristics including height, weight, body mass index, blood pressure, and laboratory measurements were compared with those of age-matched National Health and Nutritional Examination Survey comparison group.

RESULTS

Seventy-eight TGD youth with a median age of 11 years (range 8-14 years) were recruited before pubertal suppression, of whom 41 (53%) were designated male at birth, and 296 participants with a median age of 16 years (range 12-20 years) were recruited before beginning gender-affirming hormones, of whom 99 (33%) were designated male at birth. The mean high-density lipoprotein cholesterol was lower in the study participants when compared with that of National Health and Nutritional Examination Survey participants (50.6 ± 12.3 mg/dL vs. 53.3 ± 13.3 mg/dL, p = .001). Otherwise, the study cohorts were similar in terms of body mass index, proportion of overweight and obesity, blood pressure, and baseline laboratory variables.

CONCLUSIONS

Before starting gender-affirming treatment, TGD youth are physiologically similar to the general population of children and adolescents in the United States, with the exception of slightly lower high-density lipoprotein cholesterol. Evaluation of this cohort over time will define the physiological effects of pubertal blockade and gender-affirming hormone treatment.

Low Bone Mineral Density in Early Pubertal Transgender/Gender Diverse Youth: Findings From the Trans Youth Care Study

Context

Transgender youth may initiate GnRH agonists (GnRHa) to suppress puberty, a critical period for bone-mass accrual. Low bone mineral density (BMD) has been reported in late-pubertal transgender girls before gender-affirming therapy, but little is known about BMD in early-pubertal transgender youth.

Objective

To describe BMD in early-pubertal transgender youth.

Design

Cross-sectional analysis of the prospective, observational, longitudinal Trans Youth Care Study cohort.

Setting

Four multidisciplinary academic pediatric gender centers in the United States.

Participants

Early-pubertal transgender youth initiating GnRHa.

Main Outcome Measures

Areal and volumetric BMD Z-scores.

Results

Designated males at birth (DMAB) had below-average BMD Z-scores when compared with male reference standards, and designated females at birth (DFAB) had below-average BMD Z-scores when compared with female reference standards except at hip sites. At least 1 BMD Z-score was < -2 in 30% of DMAB and 13% of DFAB. Youth with low BMD scored lower on the Physical Activity Questionnaire for Older Children than youth with normal BMD, 2.32 ± 0.71 vs. 2.76 ± 0.61 (P = 0.01). There were no significant deficiencies in vitamin D, but dietary calcium intake was suboptimal in all youth.

Conclusions

In early-pubertal transgender youth, BMD was lower than reference standards for sex designated at birth. This lower BMD may be explained, in part, by suboptimal calcium intake and decreased physical activity–potential targets for intervention. Our results suggest a potential need for assessment of BMD in prepubertal gender-diverse youth and continued monitoring of BMD throughout the pubertal period of gender-affirming therapy.

Use of Gonadotropin-Releasing Hormone Analogs in Children: Update by an International Consortium

This update, written by authors designated by multiple pediatric endocrinology societies (see List of Participating Societies) from around the globe, concisely addresses topics related to changes in GnRHa usage in children and adolescents over the last decade. Topics related to the use of GnRHa in precocious puberty include diagnostic criteria, globally available formulations, considerations of benefit of treatment, monitoring of therapy, adverse events, and long-term outcome data. Additional sections review use in transgender individuals and other pediatric endocrine related conditions. Although there have been many significant changes in GnRHa usage, there is a definite paucity of evidence-based publications to support them. Therefore, this paper is explicitly not intended to evaluate what is recommended in terms of the best use of GnRHa, based on evidence and expert opinion, but rather to describe how these drugs are used, irrespective of any qualitative evaluation. Thus, this paper should be considered a narrative review on GnRHa utilization in precocious puberty and other clinical situations. These changes are reviewed not only to point out deficiencies in the literature but also to stimulate future studies and publications in this area.

Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline

Objective

To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009.

Participants

The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer.

Evidence

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

Consensus Process

Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines.

Conclusion

Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.

Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009.

PARTICIPANTS

The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines.

CONCLUSION

Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.

Enhancing Pediatric Trainees' and Students' Knowledge in Providing Care to Transgender Youth

PURPOSE

To enhance pediatric trainees' and students' knowledge of the psychosocial and medical issues facing transgender youth through a comprehensive curriculum.

METHODS

During the 2015-2016 academic year, we administered a transgender youth curriculum to fourth-year medical students, pediatric interns, psychiatry interns, and nurse practitioner students on their 1-month adolescent and young adult medicine rotation. The curriculum included six interactive, online modules and an observational experience in a multidisciplinary pediatric gender clinic. The online modules had a primary care focus with topics of general transgender terminology, taking a gender history, taking a psychosocial history, performing a sensitive physical examination, and formulating an assessment, psychosocial plan, and medical plan. At the completion of the curriculum, learners completed an evaluation that assessed change in perceived awareness and knowledge of transgender-related issues and learner satisfaction with the curriculum.

RESULTS

Twenty learners participated in the curriculum with 100% completing the curriculum evaluations, 100% reporting completing all six online modules, and 90% attending the gender clinic. Learners demonstrated a statistically significant improvement in all pre-post knowledge/awareness measures. On a Likert scale where 5 indicated very satisfied, learners' mean rating of the quality of the curriculum was 4.5 ± .7; quality of the modules was 4.4 ± .7; and satisfaction with the observational experience was 4.5 ± .8.

CONCLUSIONS

A comprehensive curriculum comprised interactive online modules and an observational experience in a pediatric gender clinic was effective at improving pediatric learners' perceived knowledge of the medical and psychosocial issues facing transgender youth. Learners also highly valued the curriculum.

Transgender youth: current concepts

In many countries throughout the world, increasing numbers of gender nonconforming/transgender youth are seeking medical services to enable the development of physical characteristics consistent with their experienced gender. Such medical services include use of agents to block endogenous puberty at Tanner stage II with subsequent use of cross-sex hormones, and are based on longitudinal studies demonstrating that those individuals who were first identified as gender dysphoric in early or middle childhood and continue to meet the mental health criteria for being transgender at early puberty are likely to be transgender as adults. This review addresses terms and definitions applicable to gender nonconforming youth, studies that shed light on the biologic determinants of gender identity, current clinical practice guidelines for transgender youth, challenges to optimal care, and priorities for research.

Research priorities for gender nonconforming/transgender youth: gender identity development and biopsychosocial outcomes

PURPOSE OF REVIEW

The review summarizes relevant research focused on prevalence and natural history of gender nonconforming/transgender youth, and outcomes of currently recommended clinical practice guidelines. This review identifies gaps in knowledge, and provides recommendations foci for future research.

RECENT FINDINGS

Increasing numbers of gender nonconforming youth are presenting for care. Clinically useful information for predicting individual psychosexual development pathways is lacking. Transgender youth are at high risk for poor medical and psychosocial outcomes. Longitudinal data examining the impact of early social transition and medical interventions are sparse. Existing tools to understand gender identity and quantify gender dysphoria need to be reconfigured to study a more diverse cohort of transgender individuals. Increasingly, biomedical data are beginning to change the trajectory of scientific investigation.

SUMMARY

Extensive research is needed to improve understanding of gender dysphoria, and transgender experience, particularly among youth. Recommendations include identification of predictors of persistence of gender dysphoria from childhood into adolescence, and a thorough investigation into the impact of interventions for transgender youth. Finally, examining the social environments of transgender youth is critical for the development of appropriate interventions necessary to improve the lives of transgender people.

Gender Variance and Dysphoria in Children and Adolescents

Gender variant and transgender youth are seeking medical care at younger ages. Pediatricians and other primary care physicians are often the first professionals who encounter such youth and their families. The goals of this article are to provide information on the epidemiology and natural history of gender variant and transgender youth, current clinical practice guidelines regarding the use of puberty blockers and cross-sex hormones for transgender youth, and limitations and challenges to optimal care.

Health care providers' comfort with and barriers to care of transgender youth

PURPOSE

To explore providers' clinical experiences, comfort, and confidence with and barriers to providing care to transgender youth.

METHODS

An online survey was administered to members of the Society for Adolescent Health and Medicine and the Pediatric Endocrine Society with items querying about clinical exposure to transgender youth, familiarity with and adherence to existing clinical practice guidelines, perceived barriers to providing transgender-related care, and comfort and confidence with providing transgender-related care. The response rate was 21.9% (n = 475).

RESULTS

Of the respondents, 66.5% had provided care to transgender youth, 62.4% felt comfortable with providing transgender medical therapy, and 47.1% felt confident in doing so. Principal barriers to provision of transgender-related care were lack of the following: training, exposure to transgender patients, available qualified mental health providers, and insurance reimbursement.

CONCLUSIONS

This study suggests that more training in transgender-related care, available qualified mental health providers, and insurance reimbursement for transgender-related care are needed.

Anti-thymocyte globulin/G-CSF treatment preserves β cell function in patients with established type 1 diabetes

BACKGROUND

Previous efforts to preserve β cell function in individuals with type 1 diabetes (T1D) have focused largely on the use of single immunomodulatory agents administered within 100 days of diagnosis. Based on human and preclinical studies, we hypothesized that a combination of low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte CSF (G-CSF) would preserve β cell function in patients with established T1D (duration of T1D >4 months and <2 years).

METHODS

A randomized, single-blinded, placebo-controlled trial was performed on 25 subjects: 17 subjects received ATG (2.5 mg/kg intravenously) followed by pegylated G-CSF (6 mg subcutaneously every 2 weeks for 6 doses) and 8 subjects received placebo. The primary outcome was the 1-year change in AUC C-peptide following a 2-hour mixed-meal tolerance test (MMTT). At baseline, the age (mean ± SD) was 24.6 ± 10 years; mean BMI was 25.4 ± 5.2 kg/m²; mean A1c was 6.5% ± 1.1%; insulin use was 0.31 ± 0.22 units/kg/d; and length of diagnosis was 1 ± 0.5 years.

RESULTS

Combination ATG/G-CSF treatment tended to preserve β cell function in patients with established T1D. The mean difference in MMTT-stimulated AUC C-peptide between treated and placebo subjects was 0.28 nmol/l/min (95% CI 0.001-0.552, P = 0.050). A1c was lower in ATG/G-CSF-treated subjects at the 6-month study visit. ATG/G-CSF therapy was associated with relative preservation of Tregs.

CONCLUSIONS

Patients with established T1D may benefit from combination immunotherapy approaches to preserve β cell function. Further studies are needed to determine whether such approaches may prevent or delay the onset of the disease.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01106157.

FUNDING

The Leona M. and Harry B. Helmsley Charitable Trust and Sanofi.

Psychological and medical care of gender nonconforming youth

Gender nonconforming (GN) children and adolescents, collectively referred to as GN youth, may seek care to understand their internal gender identities, socially transition to their affirmed genders, and/or physically transition to their affirmed genders. Because general pediatricians are often the first point of contact with the health care system for GN youth, familiarity with the psychological and medical approaches to providing care for this population is crucial. The objective of this review is to provide an overview of existing clinical practice guidelines for GN youth. Such guidelines emphasize a multidisciplinary approach with collaboration of medical, mental health, and social services/advocacy providers. Appropriate training needs to be provided to promote comprehensive, culturally competent care to GN youth, a population that has traditionally been underserved and at risk for negative psychosocial outcomes.

Approach to the patient: transgender youth: endocrine considerations

Compelling studies have demonstrated that "gender identity"--a person's inner sense of self as male, female, or occasionally a category other than male or female--is not simply a psychosocial construct, but likely reflects a complex interplay of biological, environmental, and cultural factors. An increasing number of preadolescents and adolescents, identifying as "transgender" (a transient or persistent identification with a gender different from their "natal gender"--ie, the gender that is assumed based on the physical sex characteristics present at birth), are seeking medical services to enable the development of physical characteristics consistent with their affirmed gender. Such services, including the use of agents to block endogenous puberty at Tanner stage 2 and subsequent use of cross-sex hormones, are based on longitudinal studies demonstrating that those individuals who were first identified as gender-dysphoric in early or middle childhood and who still meet the mental health criteria for being transgender at early puberty are likely to be transgender as adults. Furthermore, onset of puberty in transgender youth is often accompanied by increased "gender dysphoria"--clinically significant distress related to the incongruence between one's affirmed gender and one's "assigned (or natal) gender." Studies have shown that such distress may be ameliorated by a "gender-affirming" model of care. Although endocrinologists are familiar with concerns surrounding gender identity in patients with disorders of sex development, many providers are unfamiliar with the approach to the evaluation and management of transgender youth without a disorder of sex development. The goals of this article are to review studies that shed light on the biological underpinnings of gender identity, the epidemiology and natural history of transgenderism, current clinical practice guidelines for transgender youth, and limitations and challenges to optimal care. Prospective cohort studies focused on long-term safety and efficacy are needed to optimize medical and mental health care for transgender youth.

Contextualized analysis of a needs assessment using the Theoretical Domains Framework: a case example in endocrinology

BACKGROUND

The Theoretical Domains Framework (TDF) is a set of 14 domains of behavior change that provide a framework for the critical issues and factors influencing optimal knowledge translation. Considering that a previous study has identified optimal knowledge translation techniques for each TDF domain, it was hypothesized that the TDF could be used to contextualize and interpret findings from a behavioral and educational needs assessment. To illustrate this hypothesis, findings and recommendations drawn from a 2012 national behavioral and educational needs assessment conducted with healthcare providers who treat and manage Growth and Growth Hormone Disorders, will be discussed using the TDF.

METHODS

This needs assessment utilized a mixed-methods research approach that included a combination of: [a] data sources (Endocrinologists (n:120), Pediatric Endocrinologists (n:53), Pediatricians (n:52)), [b] data collection methods (focus groups, interviews, online survey), [c] analysis methodologies (qualitative - analyzed through thematic analysis, quantitative - analyzed using frequencies, cross-tabulations, and gap analysis). Triangulation was used to generate trustworthy findings on the clinical practice gaps of endocrinologists, pediatric endocrinologists, and general pediatricians in their provision of care to adult patients with adult growth hormone deficiency or acromegaly, or children/teenagers with pediatric growth disorders. The identified gaps were then broken into key underlying determinants, categorized according to the TDF domains, and linked to optimal behavioral change techniques.

RESULTS

The needs assessment identified 13 gaps, each with one or more underlying determinant(s). Overall, these determinants were mapped to 9 of the 14 TDF domains. The Beliefs about Consequences domain was identified as a contributing determinant to 7 of the 13 challenges. Five of the gaps could be related to the Skills domain, while three were linked to the Knowledge domain.

CONCLUSIONS

The TDF categorization of the needs assessment findings allowed recommendation of appropriate behavior change techniques for each underlying determinant, and facilitated communication and understanding of the identified issues to a broader audience. This approach provides a means for health education researchers to categorize gaps and challenges identified through educational needs assessments, and facilitates the application of these findings by educators and knowledge translators, by linking the gaps to recommended behavioral change techniques.

Teplizumab treatment may improve C-peptide responses in participants with type 1 diabetes after the new-onset period: a randomised controlled trial

AIMS/HYPOTHESIS

Type 1 diabetes results from a chronic autoimmune process continuing for years after presentation. We tested whether treatment with teplizumab (a Fc receptor non-binding anti-CD3 monoclonal antibody), after the new-onset period, affects the decline in C-peptide production in individuals with type 1 diabetes.

METHODS

In a randomised placebo-controlled trial we treated 58 participants with type 1 diabetes for 4-12 months with teplizumab or placebo at four academic centres in the USA. A central randomisation centre used computer generated tables to allocate treatments. Investigators, patients, and caregivers were blinded to group assignment. The primary outcome was a comparison of C-peptide responses to a mixed meal after 1 year. We explored modification of treatment effects in subgroups of patients.

RESULTS

Thirty-four and 29 subjects were randomized to the drug and placebo treated groups, respectively. Thirty-one and 27, respectively, were analysed. Although the primary outcome analysis showed a 21.7% higher C-peptide response in the teplizumab-treated group (0.45 vs 0.371; difference, 0.059 [95% CI 0.006, 0.115] nmol/l) (p = 0.03), when corrected for baseline imbalances in HbA(1c) levels, the C-peptide levels in the teplizumab-treated group were 17.7% higher (0.44 vs 0.378; difference, 0.049 [95% CI 0, 0.108] nmol/l, p = 0.09). A greater proportion of placebo-treated participants lost detectable C-peptide responses at 12 months (p = 0.03). The teplizumab group required less exogenous insulin (p < 0.001) but treatment differences in HbA(1c) levels were not observed. Teplizumab was well tolerated. A subgroup analysis showed that treatment benefits were larger in younger individuals and those with HbA(1c) <6.5% at entry. Clinical responders to teplizumab had an increase in circulating CD8 central memory cells 2 months after enrolment compared with non-responders.

CONCLUSIONS/INTERPRETATIONS

This study suggests that deterioration in insulin secretion may be affected by immune therapy with teplizumab after the new-onset period but the magnitude of the effect is less than during the new-onset period. Our studies identify characteristics of patients most likely to respond to this immune therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00378508

FUNDING

This work was supported by grants 2007-502, 2007-1059 and 2006-351 from the JDRF and grants R01 DK057846, P30 DK20495, UL1 RR024139, UL1RR025780, UL1 RR024131 and UL1 RR024134 from the NIH.

Persistent elevation of urine aquaporin-2 during water loading in a child with nephrogenic syndrome of inappropriate antidiuresis (NSIAD) caused by a R137L mutation in the V2 vasopressin receptor

Nephrogenic Syndrome of Inappropriate Antidiuresis (NSIAD) is a novel disease caused by a gain-of-function mutation in the V2 vasopressin receptor (V2R), which results in water overload and hyponatremia. We report the effect of water loading in a 3-year old boy with NSIAD, diagnosed in infancy, to assess urine aquaporin-2 (AQP2) excretion as a marker for V2R activation, and to evaluate the progression of the disease since diagnosis. The patient is one of the first known NSIAD patients and the only patient with a R137L mutation. Patient underwent a standard water loading test in which serum and urine sodium and osmolality, serum AVP, and urine AQP2 excretion were measured. The patient was also evaluated for ad lib fluid intake before and after the test. This patient demonstrated persistent inability to excrete free water. Only 39% of the water load (20 ml/kg) was excreted during a 4-hour period (normal ≥ 80-90%). Concurrently, the patient developed hyponatremia and serum hypoosmolality. Serum AVP levels were detectable at baseline and decreased one hour after water loading; however, urine AQP2 levels were elevated and did not suppress normally during the water load. The patient remained eunatremic but relatively hypodipsic during ad lib intake. In conclusion, this is the first demonstration in a patient with NSIAD caused by a R137L mutation in the V2R that urine AQP2 excretion is inappropriately elevated and does not suppress normally with water loading. In addition, this is the first longitudinal report of a pediatric patient with NSIAD diagnosed in infancy who demonstrates the ability to maintain eunatremia during ad lib dietary intake.

Pediatric disorders of water balance

Fluid homeostasis requires adequate water intake, regulated by an intact thirst mechanism and appropriate free water excretion by the kidneys, mediated by appropriate secretion of arginine vasopressin (AVP, also known as antidiuretic hormone). AVP exerts its antidiuretic action by binding to the X chromosome-encoded V2 vasopressin receptor (V2R), a G protein coupled receptor on the basolateral membrane of renal collecting duct epithelial cells. After V2R activation, increased intracellular cyclic adenosine monophosphate mediates shuttling of the water channel aquaporin 2 to the apical membrane of collecting duct cells, resulting in increased water permeability and antidiuresis. Clinical disorders of water balance are common, and abnormalities in many steps involving AVP secretion and responsiveness have been described. This article focuses on the principal disorders of water balance, diabetes insipidus, and the syndrome of inappropriate antidiuretic hormone secretion.

Functional characterization of vasopressin type 2 receptor substitutions (R137H/C/L) leading to nephrogenic diabetes insipidus and nephrogenic syndrome of inappropriate antidiuresis: implications for treatments

Substitution of arginine-137 of the vasopressin type 2 receptor (V2R) for histidine (R137H-V2R) leads to nephrogenic diabetes insipidus (NDI), whereas substitution of the same residue to cysteine or leucine (R137C/L-V2R) causes the nephrogenic syndrome of inappropriate antidiuresis (NSIAD). These two diseases have opposite clinical outcomes. Still, the three mutant receptors were shown to share constitutive beta-arrestin recruitment and endocytosis, resistance to vasopressin-stimulated cAMP production and mitogen-activated protein kinase activation, and compromised cell surface targeting, raising questions about the contribution of these phenomenons to the diseases and their potential treatments. Blocking endocytosis exacerbated the elevated basal cAMP levels promoted by R137C/L-V2R but not the cAMP production elicited by R137H-V2R, demonstrating that substitution of Arg137 to Cys/Leu, but not His, leads to constitutive V2R-stimulated cAMP accumulation that most likely underlies NSIAD. The constitutively elevated endocytosis of R137C/L-V2R attenuates the signaling and most likely reduces the severity of NSIAD, whereas the elevated endocytosis of R137H-V2R probably contributes to NDI. The constitutive signaling of R137C/L-V2R was not inhibited by treatment with the V2R inverse agonist satavaptan (SR121463). In contrast, owing to its pharmacological chaperone property, SR121463 increased the R137C/L-V2R maturation and cell surface targeting, leading to a further increase in basal cAMP production, thus disqualifying it as a potential treatment for patients with R137C/L-V2R-induced NSIAD. However, vasopressin was found to promote beta-arrestin/AP-2-dependent internalization of R137H/C/L-V2R beyond their already elevated endocytosis levels, raising the possibility that vasopressin could have a therapeutic value for patients with R137C/L-V2R-induced NSIAD by reducing steady-state surface receptor levels, thus lowering basal cAMP production.

Pediatric disorders of water balance

Fluid homeostasis requires adequate water intake, regulated by an intact thirst mechanism and appropriate free water excretion by the kidneys, mediated by appropriate secretion of arginine vasopressin (AVP, also known as antidiuretic hormone). AVP exerts its antidiuretic action by binding to the X chromosome-encoded V2 vasopressin receptor (V2R), a G protein-coupled receptor on the basolateral membrane of renal collecting duct epithelial cells. After V2R activation, increased intracellular cyclic adenosine monophosphate mediates shuttling of the water channel aquaporin 2 to the apical membrane of collecting duct cells, resulting in increased water permeability and antidiuresis. Clinical disorders of water balance are common, and abnormalities in many steps involving AVP secretion and responsiveness have been described. This article focuses on the principal disorders of water balance, diabetes insipidus, and the syndrome of inappropriate antidiuretic hormone secretion.

Identification, characterization and rescue of a novel vasopressin-2 receptor mutation causing nephrogenic diabetes insipidus

OBJECTIVE

X-linked nephrogenic diabetes insipidus (XNDI), caused by mutations in the V2 vasopressin receptor (V2R), is clinically distinguished from central diabetes insipidus (CDI) by elevated serum vasopressin (AVP) levels and unresponsiveness to 1-desamino-8-d-arginine vasopressin (DDAVP). We report two infants with XNDI, and present the characterization and functional rescue of a novel V2R mutation.

PATIENTS

Two male infants presented with poor growth and hypernatraemia. Both patients had measurable pretreatment serum AVP and polyuria that did not respond to DDAVP, suggesting NDI. However, both also had absent posterior pituitary bright spot on MRI, which is a finding more typical of CDI.

METHODS

The AVPR2 gene encoding V2R was sequenced. The identified novel missense mutation was re-created by site-directed mutagenesis and expressed in HEK293 cells. V2R activity was assessed by the ability of transfected cells to produce cAMP in response to stimulation with DDAVP. Membrane localization of V2R was assessed by fluorescence microscopy.

RESULTS

Patient 1 had a deletion of AVPR2; patient 2 had the novel mutation L57R. In transiently transfected HEK293 cells, DDAVP induced detectable but severely impaired L57R V2R activity compared to cells expressing wild-type V2R. Fluorescence microscopy showed that myc-tagged wild-type V2R localized to the cell membrane while L57R V2R remained intracellular. A nonpeptide V2R chaperone, SR121463, partially rescued L57R V2R function by allowing it to reach the cell membrane.

CONCLUSIONS

L57R V2R has impaired in vitro activity that can be partially improved by treatment with a V2R chaperone. The posterior pituitary hyperintensity may be absent in infants with XNDI.

Isolated adrenocorticotropic hormone deficiency presenting as an acute neurologic emergency in a peripubertal girl

Isolated adrenocorticotropic hormone (ACTH) deficiency (IAD) is extraordinarily rare, and the clinical manifestations of its accompanying adrenal insufficiency are diverse. Early-onset forms of IAD have been linked to mutations in the Tpit transcription factor gene TPIT; however, the genetic basis of juvenile- or late-onset IAD is unknown. Herein, we describe a case of a peripubertal girl with IAD and a normal TPIT gene who presented with an acute neurologic emergency, demonstrating both the variable clinical presentation of IAD and the need for continued investigation into the molecular mechanisms underlying juvenile- and late-onset IAD.

Nordihydroguaiaretic acid inhibits insulin-like growth factor signaling, growth, and survival in human neuroblastoma cells

Neuroblastoma is a common pediatric malignancy that metastasizes to the liver, bone, and other organs. Children with metastatic disease have a less than 50% chance of survival with current treatments. Insulin-like growth factors (IGFs) stimulate neuroblastoma growth, survival, and motility, and are expressed by neuroblastoma cells and the tissues they invade. Thus, therapies that disrupt the effects of IGFs on neuroblastoma tumorigenesis may slow disease progression. We show that NVP-AEW541, a specific inhibitor of the IGF-I receptor (IGF-IR), potently inhibits neuroblastoma growth in vitro. Nordihydroguaiaretic acid (NDGA), a phenolic compound isolated from the creosote bush (Larrea divaricata), has anti-tumor properties against a number of malignancies, has been shown to inhibit the phosphorylation and activation of the IGF-IR in breast cancer cells, and is currently in Phase I trials for prostate cancer. In the present study in neuroblastoma, NDGA inhibits IGF-I-mediated activation of the IGF-IR and disrupts activation of ERK and Akt signaling pathways induced by IGF-I. NDGA inhibits growth of neuroblastoma cells and induces apoptosis at higher doses, causing IGF-I-resistant activation of caspase-3 and a large increase in the fraction of sub-G0 cells. In addition, NDGA inhibits the growth of xenografted human neuroblastoma tumors in nude mice. These results indicate that NDGA may be useful in the treatment of neuroblastoma and may function in part via disruption of IGF-IR signaling.

Report of a hürthle cell neoplasm in a peripubertal girl

Thyroid nodules are rare in children compared to adults. Although most thyroid nodules are benign, the risk of malignancy is greater in pediatric patients. Papillary and follicular cell tumors account for the majority of thyroid neoplasms; Hürthle cell tumors account for less than 5%. Despite being uncommon, malignant Hürthle cell tumors are potentially more aggressive than papillary and follicular cell tumors. Therefore, distinguishing between types of thyroid neoplasms in a timely fashion has implications for prognosis and therapy. We describe a 12-year-old peripubertal girl who presented with a large right-sided thyroid nodule that was subsequently diagnosed as a Hürthle cell adenoma. To our knowledge, she represents the youngest patient with a Hürthle cell neoplasm.