Effect of Antiandrogen, Aromatase Inhibitor, and Gonadotropin-releasing Hormone Analog on Adult Height in Familial Male Precocious Puberty

Approach to the Peripubertal Patient With Short Stature

CONTEXT

The assessment and treatment of children with growth retardation is increasingly complex, and due to availability of targeted genetic sequencing, an ever-expanding number of conditions impeding growth are being identified. Among endocrine-related etiologies of short stature amenable to hormonal treatment, defects in the growth hormone (GH)-insulin-like growth factor I axis remain pre-eminent, with a multiplicity of disorders causing decreased secretion or insensitivity to GH action. Sex steroids in puberty increase epiphyseal senescence and eventual growth plate closure. This is mediated mostly via estrogen receptor (ER)α in males and females, effects that can greatly limit time available for growth.

EVIDENCE ACQUISITION

Extensive literature review through PubMed and other search engines.

EVIDENCE SYNTHESIS

Therapeutic strategies to be considered in peripubertal and pubertal children with disordered growth are here discussed, including daily and weekly GH, low-dose sex steroids, gonadotropin hormone releasing hormone (GnRH) analogues in combination with GH, aromatase inhibitors (AIs) alone and in combination with GH in boys. When used for at least 2 to 3 years, GnRH analogues combined with GH can result in meaningful increases in height. AIs used with GH permit puberty to progress in boys without hindrance, selectively decreasing estrogen, and resulting in taller height. With more than 20 years of cumulative experience in clinical use of these medications, we discuss the safety profile of these treatments.

CONCLUSION

The approach of growth retardation in the peripubertal and pubertal years must consider the sex steroid milieu and the tempo of bone acceleration. Treatment of affected children in this period must be individualized.

Short Adult Height After Rapid-tempo Puberty: When is it too Late to Treat?

A rarely reported phenomenon of rapid-tempo puberty in which the physical changes of puberty and testosterone levels increase very rapidly has not been reported outside apart from in two reviews. The resulting rapid advancement of skeletal age causes early completion of growth with shorter adult stature than expected. This appears to be genetic given its occurrence in the present report in two families, one with three brothers, one with two. We also describe potential treatments and found for the youngest that early initiation of standard therapy preserved or reclaimed adult height (AH) potential. The foreshortened AH in this situation involves rapidly advancing puberty resulting from high circulating testosterone levels leading to rapid advance in skeletal age. This was recognized earlier among younger brothers and treatment with gonadotropin-releasing analogues, growth hormone (GH) and/or aromatase inhibitor therapy (AIT) was tried. Two brothers in family A and family B were treated. Case 5 started treatment early enough so his AH was within target height (mid-parental height) range. Cases 2, 3, 4 were tried on GH and/or AIT with outcomes suggesting benefit. The prevalence and mechanism of rapid-tempo puberty requires further study. Furthermore, as illustrated by two of the current cases, this phenomenon may have a heightened prevalence, or at least may occur, in children previously diagnosed with constitutional delay of growth, underscoring the need to be cautious in assurance of a normal AH outcomes in this population, based on data from a single assessment.

Familial male-limited precocious puberty due to an activating mutation of the LHCGR: a case report and literature review

Familial male-limited precocious puberty (FMPP) is a rare form of gonadotropin-independent precocious puberty that is caused by an activating mutation of the LHCGR gene. Herein, we report a case of FMPP with a mutation of the LHCGR gene in a Korean boy with familial history of precocious puberty through 3 generations. A 16-month-old boy presented with signs of precocious puberty, including pubic hair, acne, and increased growth velocity. The patient's grandfather and father had a history of precocious puberty and profound short stature. On physical examination, the patient had prepubertal testes with pubic hair development appropriate for Tanner stage II. The stretched penile length was 7 cm (>2 standard deviation score), and observed bone age was that of a 4-year-old boy. Laboratory findings showed high serum testosterone (5.74 ng/mL [appropriate for Tanner IV-V]; normal range, <0.05 ng/mL) with suppressed luteinizing hormone (<0.07 mIU/mL) and normal serum level of follicular stimulating hormone (0.56 mIU/mL; normal range, 0.38-1.11 mIU/mL). Genetic testing revealed a pathogenic variant of LHCGR (c.1730 C>T (p.Thr577Ileu)), confirming FMPP. Bicalutamide and anastrozole were administered, and pubertal progression was sufficiently suppressed without any specific side effects. To our knowledge, this is the first case of genetically confirmed FMPP in Korea.

Sex non-specific growth charts and potential clinical implications in the care of transgender youth

Introduction

The Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) created separate growth charts for girls and boys because growth patterns and rates differ between sexes. However, scenarios exist in which this dichotomizing "girls versus boys" approach may not be ideal, including the care of non-binary youth or transgender youth undergoing transitions consistent with their gender identity. There is therefore a need for growth charts that age smooth differences in pubertal timing between sexes to determine how youth are growing as "children" versus "girls or boys" (e.g., age- and sex-neutral, compared to age- and sex-specific, growth charts).

Methods

Employing similar statistical techniques and datasets used to create the CDC 2000 growth charts, we developed age-adjusted, sex non-specific growth charts for height, weight, and body mass index (BMI), and z-score calculators for these parameters. Specifically, these were created using anthropometric data from five US cross-sectional studies including National Health Examination Surveys II-III and National Health and Nutrition Examination Surveys I-III. To illustrate contemporary clinical practice, we overlaid our charts on CDC 2000 girls and boys growth charts.

Results

39,119 youth 2-20 years old (49.5% female; 66.7% non-Hispanic White; 21.7% non-Hispanic Black) were included in the development of our growth charts, reference ranges, and z-score calculators. Respective curves were largely superimposable through around 10 years of age after which, coinciding with pubertal onset timing, differences became more apparent.

Discussion

We conclude that age-adjusted, sex non-specific growth charts may be used in clinical situations such as transgender youth in which standard "girls versus boys" growth charts are not ideal. Until longitudinal auxological data are available in these populations, our growth charts may help to assess a transgender youth's growth trajectory and weight classification, and expectations surrounding these.

Management of Growth Disorders in Puberty: GH, GnRHa, and Aromatase Inhibitors: A Clinical Review

Pubertal children with significant growth retardation represent a considerable therapeutic challenge. In growth hormone (GH) deficiency, and in those without identifiable pathologies (idiopathic short stature), the impact of using GH is significantly hindered by the relentless tempo of bone age acceleration caused by sex steroids, limiting time available for growth. Estrogen principally modulates epiphyseal fusion in females and males. GH production rates and growth velocity more than double during puberty, and high-dose GH use has shown dose-dependent increases in linear growth, but also can raise insulin-like growth factor I concentrations supraphysiologically, and increase treatment costs. Gonadotropin-releasing hormone analogs (GnRHas) suppress physiologic puberty, and when used in combination with GH can meaningfully increase height potential in males and females while rendering adolescents temporarily hypogonadal at a critical time in development. Aromatase inhibitors (AIs) block androgen to estrogen conversion, slowing down growth plate fusion, while allowing normal virilization in males and stimulating longitudinal bone growth via androgen receptor effects on the growth plate. Here, we review the physiology of pubertal growth, estrogen and androgen action on the epiphyses, and the therapeutic impact of GH, alone and in combination with GnRHa and with AIs. The pharmacology of potent oral AIs, and pivotal work on their efficacy and safety in children is also reviewed. Time-limited use of AIs is a viable alternative to promote growth in pubertal males, particularly combined with GH. Use of targeted growth-promoting therapies in adolescence must consider the impact of sex steroids on growth plate fusion, and treatment should be individualized.

Familial Male-limited Precocious Puberty (FMPP) and Testicular Germ Cell Tumors

OBJECTIVE

The purpose of this study is to report development of a malignant testicular germ cell tumor (GCT) in 2 young adult males with familial male-limited precocious puberty (FMPP) because of LHCGR pathogenic variants in 2 families. Secondarily, to study the possible relation between FMPP and testicular tumors and to investigate whether FMPP might predispose to development of malignant testicular tumors in adulthood a literature review is conducted.

METHODS

Data on 6 cases in 2 families are obtained from the available medical records. In addition, a database search is performed in Cochrane, PubMed, and Embase for studies that report on a possible link between FMPP and testicular tumors.

RESULTS

The characteristics of 6 males with FMPP based on activating LH receptor (LHCGR) germline pathogenic variants are described, as are details of the testicular GCTs. Furthermore, a literature review identified 4 more patients with signs of FMPP and a (precursor of) testicular GCT in adolescence or adulthood (age 15-35 years). Additionally, 12 patients with signs of precocious puberty and, simultaneously, occurrence of a Leydig cell adenoma or Leydig cell hyperplasia are reported.

CONCLUSION

There is a strong suggestion that FMPP might increase the risk of development of testicular GCTs in early adulthood compared with the risk in the general population. Therefore, prolonged patient monitoring from mid-pubertal age onward including instruction for self-examination and periodic testicular ultrasound investigation in patients with a germline LHCGR pathogenic variant might contribute to early detection and thus early treatment of testicular GCT.

Precocious Puberty in a Boy With Bilateral Leydig Cell Tumors due to a Somatic Gain-of-Function LHCGR Variant

Context

Autosomal dominant and rarely de novo gain-of-function variants in the LHCGR gene are associated with precocious male puberty, while somatic LHCGR variants have been found in isolated Leydig cell adenomas and Leydig cell hyperplasia. Bilateral diffuse Leydig cell tumor formation in peripheral precocious male puberty has not been reported.

Case Description

We present a boy with gonadotropin-independent precocious puberty and rapid virilization beginning in infancy resistant to standard therapy. Treatment with abiraterone in addition to letrozole and bicalutamide proved effective. Bilateral diffuse Leydig cell tumors were identified at age 5 years.

Results

Whole-genome sequencing of tumor and blood samples was performed. The patient was confirmed to have bilateral, diffuse Leydig cell tumors harboring the somatic, gain-of-function p.Asp578His variant in the LHCGR gene. Digital droplet polymerase chain reaction of the LHCGR variant performed in tumor and blood samples detected low levels of this same variant in the blood.

Conclusion

We report a young boy with severe gonadotropin-independent precocious puberty beginning in infancy who developed bilateral diffuse Leydig cell tumors at age 5 years due to a somatic gain-of-function p.Asp578His variant in LHCGR. The gain-of-function nature of the LHCGR variant and the developmental timing of the somatic mutation likely play a role in the risk of tumor formation. Abiraterone (a CYP17A1 inhibitor), in combination with an antiandrogen, aromatase inhibitor, and glucocorticoid, appears to be an effective therapy for severe peripheral precocious puberty in boys.

Long-Term Treatment With Letrozole in a Boy With Familial Male-Limited Precocious Puberty

BACKGROUND

The long-term follow-up in children with familial male-limited precocious puberty (FMPP) who were treated with letrozole, triptorelin, and spironolactone is limited, especially considering the efficiency and safety.

OBJECTIVE

We describe the clinical characteristics and long-term treatment with letrozole on adult height of a boy diagnosed with FMPP, confirmed by analysis of the LHCGR gene.

METHODS

Physical examinations, bone age (BA), testosterone, and gonadotropin levels were measured as well as gene sequencing of the proband and parents.

RESULTS

The boy was referred to the hospital at 3.1 years of age due to peripheral precocious puberty. His height was 116.8cm (+5.1SD) and BA was 9 years. Genetic analysis revealed a patrilineal c.1703C>T.(p.Ala568Val) mutation of the LHCGR gene. After treating with letrozole for 1.6 years, the height according to BA went from -3.52SD to -2.82SD. Triptorelin was added at age 4.7 years based on both the evidence of central puberty and his growth velocity according to BA. During the 6.9 years of treatment, he had a height gain of 51.9cm, and BA increased 5.2 years. At age 10, his present height is 168.7cm (0.05SD) and BA is 14.7 years. No adverse effects of treatment were encountered.

CONCLUSION

A patrilineal mutation of the LHCGR gene has been identified in a boy with FMPP. His height is 168.7cm (-0.05SD) which is approaching his adult height after long-term treatment with letrozole, triptorelin, and spironolactone.

Diagnosis and management of precocious sexual maturation: an updated review

The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. It is classified as central precocious puberty when premature maturation of the hypothalamic-pituitary-gonadal axis occurs, and as peripheral precocious puberty when there is excessive secretion of sex hormones, independent of gonadotropin secretion. Precocious sexual maturation is more common in girls, generally central precocious puberty of idiopathic origin. In boys, it tends to be linked to central nervous system abnormalities. Clinical evaluation should include a detailed history and physical examination, including anthropometric measurements, calculation of growth velocity, and evaluation of secondary sexual characteristics. The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. Hormonal assessment and imaging are required for diagnosis and identification of the etiology. Genetic testing should be considered if there is a family history of precocious puberty or other clinical features suggestive of a genetic syndrome. Long-acting gonadotropin-releasing hormone analogs are the standard of care for central precocious puberty management, while peripheral precocious puberty management depends on the etiology.Conclusion: The aim of this review is to address the epidemiology, etiology, clinical assessment, and management of precocious sexual maturation. What is Known: • The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. • Long-acting gonadotropin-releasing hormone agonist (GnRHa) is the standard of care for CPP management, and adequate hormone suppression results in the stabilization of pubertal progression, a decline in growth velocity, and a decrease in bone age advancement. What is New: • Most cases of precocious sexual maturation are gonadotropin-dependent and currently assumed to be idiopathic, but mutations in genes involved in pubertal development have been identified, such as MKRN3 and DLK1. • A different preparation of long-acting GnRHa is now available: 6-month subcutaneous injection.

A Case of Familial Male-limited Precocious Puberty with a Novel Mutation

Familial male-limited precocious puberty (FMPP), also known as testotoxicosis, is a rare cause of precocious puberty in males. It is caused by a mutation in the luteinizing hormone/chorionic gonadotropin receptor (LHCGR) gene, resulting in the receptor being constitutively activated. This causes excessive production of testosterone, leading to precocious puberty in males. Generally, boys present with signs of puberty, such as pubic hair growth, acne, and increased height velocity around the age of 2-4 years old. Like any other cause of precocious puberty, the goal of treatment is to prevent virilization and also delay closure of the epiphyseal plates to maintain adult height potential. Treatment, therefore, is aimed at decreasing the effects of testosterone, as well as stopping the conversion of testosterone to estrogen. Little is known about the long-term effects of treatment because the disorder is so rare. However, studies using bicalutamide and anastrozole have been promising. In this report, we present a boy with FMPP with a novel mutation in the LHCGR gene, who has been responding well to therapy using both drugs.

Anti-Müllerian hormone and letrozole levels in boys with constitutional delay of growth and puberty treated with letrozole or testosterone

STUDY QUESTION

Does treatment of constitutional delay of growth and puberty (CDGP) in boys with aromatase inhibitor letrozole (Lz) or conventional low-dose testosterone (T) have differing effects on developing seminiferous epithelium?

SUMMARY ANSWER

Anti-Müllerian hormone (AMH) declined similarly in both treatment groups, and the two Sertoli cell-derived markers (AMH and inhibin B (iB)) exhibited differing responses to changes in gonadotrophin milieu.

WHAT IS KNOWN ALREADY

Boys with CDGP may benefit from puberty-inducing medication. Peroral Lz activates gonadotrophin secretion, whereas intramuscular low-dose T may transiently suppress gonadotrophins and iB.

STUDY DESIGN, SIZE, DURATION

Sera of 28 boys with CDGP who participated in a randomised, controlled, open-label trial at four paediatric centres in Finland between August 2013 and January 2017 were analysed. The patients were randomly assigned to receive either Lz (2.5 mg/day) (n = 15) or T (1 mg/kg/month) (n = 13) for 6 months.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The 28 patients were at least 14 years of age, showed first signs of puberty, wanted medical attention for CDGP and were evaluated at 0, 3, 6 and 12 months of visits. AMH levels were measured with an electrochemiluminescence immunoassay and Lz levels with liquid chromatography coupled with tandem mass spectrometry.

MAIN RESULTS AND THE ROLE OF CHANCE

AMH levels decreased in both treatment groups during the 12-month follow-up (P < 0.0001). Between 0 and 3 months, the changes in gonadotrophin levels (increase in the Lz group, decrease in the T group) correlated strongly with the changes in levels of iB (FSH vs iB, r = 0.55, P = 0.002; LH vs iB, r = 0.72, P < 0.0001), but not with the changes in AMH (P = NS). At 12 months, AMH levels did not differ between the groups (P = NS). Serum Lz levels (range, 124-1262 nmol/L) were largely explained by the Lz dose per weight (at 3 months r = 0.62, P = 0.01; at 6 months r = 0.52, P = 0.05). Lz levels did not associate with changes in indices of hypothalamic-pituitary-gonadal axis activity or Sertoli cell markers (in all, P = NS).

LIMITATIONS, REASONS FOR CAUTION

The original trial was not blinded for practical reasons and included a limited number of participants.

WIDER IMPLICATIONS OF THE FINDINGS

In early puberty, treatment-induced gonadotrophin stimulus was unable to counteract the androgen-mediated decrease in AMH, while changes in iB levels were associated with changes in gonadotrophin levels. AMH decreased similarly in both groups during the treatment, reassuring safety of developing seminiferous epithelium in both treatment approaches. Since a fixed dose of Lz induced variable serum Lz levels with a desired puberty-promoting effect in all boys, more research is needed to aim at a minimal efficient dose per weight.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Academy of Finland, the Foundation for Pediatric Research, the Emil Aaltonen Foundation, Sigrid Juselius Foundation and Helsinki University Hospital Research Funds. The authors have nothing to disclose.

TRIAL REGISTRATION NUMBER

NCT01797718.

Should Skeletal Maturation Be Manipulated for Extra Height Gain?

Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI). These agents have been investigated in children with growth disorders (off-label), either alone or in combination with recombinant human growth hormone (rhGH). GnRHa is effective in attaining a normal adult height (AH) in the treatment of children with central precocious puberty, but its effect in short children with normal timing of puberty is equivocal. If rhGH-treated children with growth hormone deficiency or those who were born small-for-gestational age are still short at pubertal onset, co-treatment with a GnRHa for 2-3 years increases AH. A similar effect was seen by adding rhGH to GnRHa treatment of children with central precocious puberty with a poor AH prediction and by adding rhGH plus GnRHa to children with congenital adrenal hyperplasia with a poor predicted adult height on conventional treatment with gluco- and mineralocorticoids. In girls with idiopathic short stature and relatively early puberty, rhGH plus GnRHa increases AH. Administration of letrozole to boys with constitutional delay of growth puberty may increase AH, and rhGH plus anastrozole may increase AH in boys with growth hormone deficiency or idiopathic short stature, but the lack of data on attained AH and potential selective loss-of-follow-up in several studies precludes firm conclusions. GnRHas appear to have a good overall safety profile, while for aromatase inhibitors conflicting data have been reported.

Glycoprotein G-protein Coupled Receptors in Disease: Luteinizing Hormone Receptors and Follicle Stimulating Hormone Receptors

Signal transduction by luteinizing hormone receptors (LHRs) and follicle-stimulating hormone receptors (FSHRs) is essential for the successful reproduction of human beings. Both receptors and the thyroid-stimulating hormone receptor are members of a subset of G-protein coupled receptors (GPCRs) described as the glycoprotein hormone receptors. Their ligands, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and a structurally related hormone produced in pregnancy, human chorionic gonadotropin (hCG), are large protein hormones that are extensively glycosylated. Although the primary physiologic functions of these receptors are in ovarian function and maintenance of pregnancy in human females and spermatogenesis in males, there are reports of LHRs or FSHRs involvement in disease processes both in the reproductive system and elsewhere. In this review, we evaluate the aggregation state of the structure of actively signaling LHRs or FSHRs, their functions in reproduction as well as summarizing disease processes related to receptor mutations affecting receptor function or expression in reproductive and non-reproductive tissues. We will also present novel strategies for either increasing or reducing the activity of LHRs signaling. Such approaches to modify signaling by glycoprotein receptors may prove advantageous in treating diseases relating to LHRs or FSHRs function in addition to furthering the identification of new strategies for modulating GPCR signaling.

Precocious puberty

Precocious puberty (PP) is a common reason for referral to pediatric endocrinology clinics, with a strong female predominance. PP is a broad term encompassing benign variants of normal development, gonadotropin-dependent precious puberty (GDPP), and gonadotropin-independent precocious puberty (GIPP). This article reviews the definitions, physiology, clinical presentation, evaluation and treatment of these conditions.

TESTOTOXICOSIS WITH AN EPISODIC COURSE: AN UNUSUAL CASE WITHIN A SERIES

Objective

To describe an unusual case of familial male precocious puberty (FMPP) characterized by periodic remission compared to a series of boys with typical testotoxicosis.

Methods

Medical records of boys with FMPP followed at our institution from 2001-2017 were reviewed. Variables analyzed included age, family history, physical exam, hormone levels, bone age, and treatment.

Results

A boy of age 2 years 10 months presented with growth acceleration and masturbatory behaviors. On exam, he had 6-mL testes, an enlarged phallus (10.5 × 2.5 cm), and Tanner 2 pubic hair. Testosterone was 242 ng/dL (normal level, ≤30 ng/dL). Genetic testing revealed an Asp578Gly luteinizing hormone receptor mutation confirming FMPP. Anastrozole 1 mg and bicalutamide 50 mg daily were started. During 7.5 years of follow-up, two periods of spontaneous remission occurred lasting >3 years and 10 months, respectively. Both were characterized by prepubertal testosterone levels (10 to 28 ng/dL) and arrested pubertal development off therapy. Relapses were marked by elevated testosterone, growth acceleration, and pubertal progression. Ten additional boys aged 3.46 ± 0.72 years with FMPP were identified, one of whom also had an Asp578Gly mutation. Average testosterone at presentation was 335 ± 193 ng/dL (range, 146 to 778 ng/dL) and average bone age/chronologic age was 2.02 ± 0.47. All were treated with bicalutamide and anastrozole or letrozole.

Conclusion

We report a case of intermittent FMPP in contrast to a series of boys with a characteristic clinical course. To our knowledge, a similar case has not previously been reported. Our case expands the clinical spectrum of this rare condition.

Peripheral precocious puberty including congenital adrenal hyperplasia: causes, consequences, management and outcomes

Peripheral precocious puberty results from peripheral production of sex steroids independent of activation of the hypothalamic-pituitary gonadal axis. It is much less common than central precocious puberty. Causes are variable and can be congenital or acquired. In this review, we will discuss the diagnosis and management of the most common etiologies including congenital adrenal hyperplasia, McCune Albright syndrome, familial male-limited precocious puberty, and adrenal and gonadal tumors.

A Case of Familial Male-Limited Precocious Puberty in a Child With Klinefelter Syndrome

Familial male-limited precocious puberty (FMPP) is an autosomal dominant, male-limited disorder that causes peripheral precocious puberty in boys. Klinefelter syndrome (47, XXY) is the most common chromosomal aberration in males with associated infertility, hypogonadism, and learning disability. We report here a case of Klinefelter syndrome in a patient with FMPP. A 6-year-old boy was referred to our pediatric endocrinology department for accelerated linear growth and premature pubic hair development. He was diagnosed with FMPP based on clinical, laboratory, and genetic sequencing. Increased levels of gonadotropins prompted further investigation, leading to a subsequent diagnosis of Klinefelter syndrome through karyotype analysis. This case illustrates that patients with FMPP and elevated gonadotropins should encourage further investigation by physicians. We recommend the use of karyotype analysis in such patients who are not receiving aromatase inhibitor therapy. We hypothesize that his mutation or pretreatment with aromatase inhibitors may have a protective effect on testosterone production and sperm viability.