Progressive reduction of relative height in childhood predicts adult stature below target height in boys with constitutional delay of growth and puberty

Key features of puberty onset and progression can help distinguish self-limited delayed puberty from congenital hypogonadotrophic hypogonadism

Introduction

Delayed puberty (DP) is a frequent concern for adolescents. The most common underlying aetiology is self-limited DP (SLDP). However, this can be difficult to differentiate from the more severe condition congenital hypogonadotrophic hypogonadism (HH), especially on first presentation of an adolescent patient with DP. This study sought to elucidate phenotypic differences between the two diagnoses, in order to optimise patient management and pubertal development.

Methods

This was a study of a UK DP cohort managed 2015-2023, identified through the NIHR clinical research network. Patients were followed longitudinally until adulthood, with a definite diagnosis made: SLDP if they had spontaneously completed puberty by age 18 years; HH if they had not commenced (complete, cHH), or had commenced but not completed puberty (partial, pHH), by this stage. Phenotypic data pertaining to auxology, Tanner staging, biochemistry, bone age and hormonal treatment at presentation and during puberty were retrospectively analysed.

Results

78 patients were included. 52 (66.7%) patients had SLDP and 26 (33.3%) patients had HH, comprising 17 (65.4%) pHH and 9 (34.6%) cHH patients. Probands were predominantly male (90.4%). Male SLDP patients presented with significantly lower height and weight standard deviation scores than HH patients (height p=0.004, weight p=0.021). 15.4% of SLDP compared to 38.5% of HH patients had classical associated features of HH (micropenis, cryptorchidism, anosmia, etc. p=0.023). 73.1% of patients with SLDP and 43.3% with HH had a family history of DP (p=0.007). Mean first recorded luteinizing hormone (LH) and inhibin B were lower in male patients with HH, particularly in cHH patients, but not discriminatory. There were no significant differences identified in blood concentrations of FSH, testosterone or AMH at presentation, or in bone age delay.

Discussion

Key clinical markers of auxology, associated signs including micropenis, and serum inhibin B may help distinguish between SLDP and HH in patients presenting with pubertal delay, and can be incorporated into clinical assessment to improve diagnostic accuracy for adolescents. However, the distinction between HH, particularly partial HH, and SLDP remains problematic. Further research into an integrated framework or scoring system would be useful in aiding clinician decision-making and optimization of treatment.  .

Use of letrozole to augment height outcome in pubertal boys: a retrospective chart review

OBJECTIVES

We describe growth patterns and predicted adult height (PAH) in pubertal boys treated with letrozole and evaluate the potential predictors of growth responses.

METHODS

We performed a retrospective analysis of data from 2002 to 2020. All subjects were treated for ≥6 months and had at least 3 height measurements to calculate the growth velocity (GV) before and during treatment. We evaluated growth measurements, bone age, and biochemical parameters before, during and after treatment.

RESULTS

A total of 59 subjects aged 12.7 (± 1.7) years old were included. At treatment initiation, bone age was 13.1 (± 1.5) years and predicted adult height (PAH) was 163.8 (± 9.9) cm compared to mid-parental height of 172.4 (± 5.8) cm. Growth velocity decreased during letrozole therapy and rebounded after completion. Sub-analysis of 26 subjects with bone age data available at baseline and at least 1 year later showed a trend to modest increase in PAH. In boys simultaneously receiving growth hormone (rhGH), the change in PAH was significantly more (3.2 cm, p<0.05) compared to those treated with letrozole alone.

CONCLUSIONS

We show that letrozole appropriately slows down skeletal maturation and GV responses are variable. Possible negative predictors include lower baseline GV and advanced bone age. A small positive trend in PAH with letrozole therapy is augmented by simultaneous use of rhGH. Future randomized controlled trials are needed to better understand which group of patients will benefit from treatment.

Deciphering short stature in children

Short stature is a common reason for referral to pediatric endocrinologists. Multiple factors, including genetic, prenatal, postnatal, and local environmental factors, can impair growth. The majority of children with short stature, which can be defined as a height less than 2 standard deviation score below the mean, are healthy. However, in some cases, they may have an underlying relevant disease; thus, the aim of clinical evaluation is to identify the subset of children with pathologic conditions, for example growth hormone deficiency or other hormonal abnormalities, Turner syndrome, inflammatory bowel disease, or celiac disease. Prompt identification and management of these children can prevent excessive short stature in adulthood. In addition, a thorough clinical assessment may allow evaluation of the severity of short stature and likely growth trajectory to identify the most effective interventions. Consequently, appropriate diagnosis of short stature should be performed as early as possible and personalized treatment should be started in a timely manner. An increase in knowledge and widespread availability of genetic and epigenetic testing in clinical practice in recent years has empowered the diagnostic process and appropriate treatment for short stature. Furthermore, novel treatment approaches that can be used both as diagnostic tools and as therapeutic agents have been developed. This article reviews the diagnostic approach to children with short stature, discusses the main causes of short stature in children, and reports current therapeutic approaches and possible future treatments.

Diagnosis, Genetics, and Therapy of Short Stature in Children: A Growth Hormone Research Society International Perspective

The Growth Hormone Research Society (GRS) convened a Workshop in March 2019 to evaluate the diagnosis and therapy of short stature in children. Forty-six international experts participated at the invitation of GRS including clinicians, basic scientists, and representatives from regulatory agencies and the pharmaceutical industry. Following plenary presentations addressing the current diagnosis and therapy of short stature in children, breakout groups discussed questions produced in advance by the planning committee and reconvened to share the group reports. A writing team assembled one document that was subsequently discussed and revised by participants. Participants from regulatory agencies and pharmaceutical companies were not part of the writing process. Short stature is the most common reason for referral to the pediatric endocrinologist. History, physical examination, and auxology remain the most important methods for understanding the reasons for the short stature. While some long-standing topics of controversy continue to generate debate, including in whom, and how, to perform and interpret growth hormone stimulation tests, new research areas are changing the clinical landscape, such as the genetics of short stature, selection of patients for genetic testing, and interpretation of genetic tests in the clinical setting. What dose of growth hormone to start, how to adjust the dose, and how to identify and manage a suboptimal response are still topics to debate. Additional areas that are expected to transform the growth field include the development of long-acting growth hormone preparations and other new therapeutics and diagnostics that may increase adult height or aid in the diagnosis of growth hormone deficiency.

Effects of the Timing of Sex-Steroid Exposure in Adolescence on Adult Health Outcomes

CONTEXT

Variation in pubertal timing is associated with a wide range of adult risks and outcomes, but it is unclear whether these associations are causal, and it is largely unknown whether these associations can be modified by treatment.

EVIDENCE ACQUISITION

We conducted PubMed searches to identify Mendelian randomization (MR) studies on the influence of pubertal timing on adult health and studies on sex-steroid treatment of the following conditions associated with reduced reproductive endocrine function in adolescence: constitutional delay, Turner syndrome, and Klinefelter syndrome.

EVIDENCE SYNTHESIS

Results of MR studies suggest that earlier pubertal timing increases body mass index; increases risk for breast, ovarian, endometrial, and prostate cancers; elevates fasting glucose levels and blood pressure; impairs lung capacity and increases risk for asthma; leads to earlier sexual intercourse and first birth; decreases time spent in education; and increases depressive symptoms in adolescence. Later pubertal timing appears to lower bone mineral density (BMD). Although studies of constitutional delay have not shown that sex-steroid treatment alters adult height or BMD, studies of girls with Turner syndrome and boys with Klinefelter syndrome suggest that earlier initiation of sex-steroid treatment improves physical and neurocognitive outcomes.

CONCLUSIONS

Despite having some limitations, MR studies suggest that pubertal timing causally influences many adult conditions and disease risks. Studies of Turner syndrome and Klinefelter syndrome suggest that earlier sex-steroid exposure may have short- and long-term benefits. The mechanisms underlying these findings and the effects of trends and treatments affecting pubertal timing remain to be determined.

Delayed Puberty-Phenotypic Diversity, Molecular Genetic Mechanisms, and Recent Discoveries

This review presents a comprehensive discussion of the clinical condition of delayed puberty, a common presentation to the pediatric endocrinologist, which may present both diagnostic and prognostic challenges. Our understanding of the genetic control of pubertal timing has advanced thanks to active investigation in this field over the last two decades, but it remains in large part a fascinating and mysterious conundrum. The phenotype of delayed puberty is associated with adult health risks and common etiologies, and there is evidence for polygenic control of pubertal timing in the general population, sex-specificity, and epigenetic modulation. Moreover, much has been learned from comprehension of monogenic and digenic etiologies of pubertal delay and associated disorders and, in recent years, knowledge of oligogenic inheritance in conditions of GnRH deficiency. Recently there have been several novel discoveries in the field of self-limited delayed puberty, encompassing exciting developments linking this condition to both GnRH neuronal biology and metabolism and body mass. These data together highlight the fascinating heterogeneity of disorders underlying this phenotype and point to areas of future research where impactful developments can be made.

Congenital Hypogonadotrophic Hypogonadism: Minipuberty and the Case for Neonatal Diagnosis

Congenital hypogonadotrophic hypogonadism (CHH) is a rare but important etiology of pubertal failure and infertility, resulting from impaired gonadotrophin-releasing hormone secretion or action. Despite the availability of effective hormonal therapies, the majority of men with CHH experience unsatisfactory outcomes, including chronic psychosocial and reproductive sequelae. Early detection and timely interventions are crucial to address the gaps in medical care and improve the outlook for these patients. In this paper, we review the clinical implications of missing minipuberty in CHH and therapeutic strategies that can modify the course of disease, as well as explore a targeted approach to identifying affected male infants by integrating clinical and biochemical data in the early postnatal months.

Evaluation of near final height in boys with constitutional delay in growth and puberty

BACKGROUND

This study was conducted to find out whether boys with constitutional delay in growth and puberty (CDGP) could attain their target height and predicted adult height (PAH) in adulthood or not.

METHODS

After measuring the height, weight, pubertal stage, parental height and bone age data of the patients at their first presentation were extracted from the files and their height and weight were measured at the end of the study, wrist X-Ray was performed in order to determine the bone age. PAH was calculated using Bayley-Pinneau method and target height was estimated by mid parental height. Final or near final heights of the patients were measured and compared with the target height and PAH.

RESULTS

The mean age at presentation and the end of study was 15.2 ± 0.95, 20 ± 0.75 years respectively. Mean of bone age at the beginning of study was 12.97 ± 1 years and at the end of study were 17.6 ± 0.58 years. Mean of delayed bone age was 2.2 ± 0.82 years. Mean of the primary measured heights was 150.16 ± 7 cm (138-160 cm). Mean of final or near final heights was 165.7 ± 2.89 cm (161-170.5 cm). Final or near final heights in our subjects were smaller than either their PAH (165.7 ± 2.89 vs 170.7 ± 5.17) (P value <0.005) or target height (165.7 ± 2.89 vs 171.8 ± 4.65) (P value <0.0001).

CONCLUSION

Most patients with CDGP do not reach their target height or predicted adult height; they are usually shorter than their parents and general population. Such patients need to be followed up until they reach their final height and, in some cases, adjunctive medical treatment might be indicated.

Fertility Issues for Patients with Hypogonadotropic Causes of Delayed Puberty

Delayed puberty presenting with low gonadotropins has multiple causes. Self-limited delay (constitutional delay) is generally considered benign, but adult height and bone mineral density may be compromised, and fertility has not been studied. Functional hypogonadotropic hypogonadism due to a stressor is thought to resolve with removal of the stressor, but reproductive endocrine dysfunction can sometimes persist. Most but not all patients with idiopathic hypogonadotropic hypogonadism, a typically long-lasting condition, can achieve fertility with exogenous hormone therapy. Future studies are needed to determine fertility outcomes in self-limited delayed puberty and to more clearly define prognostic factors for fertility in functional and idiopathic hypogonadotropic hypogonadism.

A shared genetic basis for self-limited delayed puberty and idiopathic hypogonadotropic hypogonadism

CONTEXT

Delayed puberty (DP) is a common issue and, in the absence of an underlying condition, is typically self limited. Alhough DP seems to be heritable, no specific genetic cause for DP has yet been reported. In contrast, many genetic causes have been found for idiopathic hypogonadotropic hypogonadism (IHH), a rare disorder characterized by absent or stalled pubertal development.

OBJECTIVE

The objective of this retrospective study, conducted at academic medical centers, was to determine whether variants in IHH genes contribute to the pathogenesis of DP.

SUBJECTS AND OUTCOME MEASURES

Potentially pathogenic variants in IHH genes were identified in two cohorts: 1) DP family members of an IHH proband previously found to have a variant in an IHH gene, with unaffected family members serving as controls, and 2) DP individuals with no family history of IHH, with ethnically matched control subjects drawn from the Exome Aggregation Consortium.

RESULTS

In pedigrees with an IHH proband, the proband's variant was shared by 53% (10/19) of DP family members vs 12% (4/33) of unaffected family members (P = .003). In DP subjects with no family history of IHH, 14% (8/56) had potentially pathogenic variants in IHH genes vs 5.6% (1 907/33 855) of controls (P = .01). Potentially pathogenic variants were found in multiple DP subjects for the genes IL17RD and TAC3.

CONCLUSIONS

These findings suggest that variants in IHH genes can contribute to the pathogenesis of self-limited DP. Thus, at least in some cases, self-limited DP shares an underlying pathophysiology with IHH.

Transition in endocrinology: induction of puberty

Puberty is the period during which we attain adult secondary sexual characteristics and reproductive capability. Its onset depends upon reactivation of pulsative GNRH, secretion from its relative quiescence during childhood, on the background of intact potential for pituitary-gonadal function. This review is intended: to highlight those current practices in diagnosis and management that are evidence based and those that are not; to help clinicians deal with areas of uncertainty with reference to physiologic first principles; by sign-posting relevant data arising from other patient groups with shared issues; to illustrate how recent scientific advances are (or should be) altering clinician perceptions of pubertal delay; and finally, to emphasise that the management of men and women presenting in advanced adult life with absent puberty cannot simply be extrapolated from paediatric practice. There is a broad spectrum of pubertal timing that varies among different populations, separated in time and space. Delayed puberty usually represents an extreme of the normal, a developmental pattern referred to as constitutional delay of growth and puberty (CDGP), but organic defects of the hypothalamo-pituitary-gonadal axis predisposing to hypogonadism may not always be initially distinguishable from it. CDGP and organic, or congenital hypogonadotrophic hypogonadism are both significantly more common in boys than girls. Moreover, around 1/3 of adults with organic hypogonadotrophic hypogonadism had evidence of partial puberty at presentation and, confusingly, some 5-10% of these subsequently may exhibit recovery of endogenous gonadotrophin secretion, including men with Kallmann syndrome. However, the distinction is crucial as expectative ('watch-and-wait') management is inappropriate in the context of hypogonadism. The probability of pubertal delay being caused by organic hypogonadism rises exponentially both with increasing age at presentation and the presence of associated 'red flag' clinical features. These 'red flags' comprise findings indicating lack of prior 'mini-puberty' (such as cryptorchidism or micropenis), or the presence of non-reproductive congenital defects known to be associated with specific hypogonadal syndromes, e.g. anosmia, deafness, mirror movements, renal agenesis, dental/digital anomalies, clefting or coloboma would be compatible with Kallmann (or perhaps CHARGE) syndrome. In children, interventions (whether in the form or treatment or simple reassurance) have been historically directed at maximising height potential and minimising psychosocial morbidity, though issues of future fertility and bone density potential are now increasingly 'in the mix'. Apubertal adults almost invariably harbour organic hypogonadism, requiring sensitive acknowledgement of underlying personal issues and the timely introduction of sex hormone replacement therapy at more physiological doses.

[Androgenic treatment of male hypogonadism]

The diagnosis of male hypogonadism should be clearly established on a clinical and biological basis before considering the initiation of a substitutive treatment with androgens. A careful evaluation of advantages, constraints and limitations of the treatment should be done previously. The potential advantages of an androgenic substitution include an improvement of the symptoms of hypogonadism and the prevention of its bone and metabolic consequences. Absolute (namely prostatic) or relative contraindications should be detected before starting any substitution. The modalities of treatment will be adapted to both the patient's age and the goals to reach. The different available formulations do not induce a similar pattern of plasma testosterone levels. Patches, gel applications and long-acting intramuscular formulations [injected every 3 months] result in stable plasma levels in the physiologic range. The main limitation to their use is linked to a financial aspect as they are not the object of any refund. A careful survey (on clinical, biological and radiological basis) should be established after starting the substitutive treatment with androgens.

An approach to constitutional delay of growth and puberty

Constitutional delay of growth and puberty is a transient state of hypogonadotropic hypogonadism associated with prolongation of childhood phase of growth, delayed skeletal maturation, delayed and attenuated pubertal growth spurt, and relatively low insulin-like growth factor-1 secretion. In a considerable number of cases, the final adult height (Ht) does not reach the mid-parental or the predicted adult Ht for the individual, with some degree of disproportionately short trunk. In the pre-pubertal male, testosterone (T) replacement therapy can be used to induce pubertal development, accelerate growth and relieve the psychosocial complaints of the adolescents. However, some issues in the management are still unresolved. These include type, optimal timing, dose and duration of sex steroid treatment and the possible use of adjunctive or alternate therapy including: oxandrolone, aromatase inhibitors and human growth hormone.

Disorders of pubertal development

BACKGROUND

Puberty is an extremely important phase in the physical and psychosocial development of the adolescent.

METHODS

Selective literature review.

RESULTS

The diagnosis of abnormal puberty requires thorough knowledge of normal pubertal development and of the variations of normal puberty as well as its pathology. Variations of normal pubertal development can be expected, by definition, to occur at a frequency of roughly 3%. A detailed history is the first step in the diagnostic evaluation of a normal variant or an abnormal puberty. Further evaluation includes laboratory testing (estradiol, testosterone, and the results of a GnRH test, among others) and imaging studies (x-ray of the left hand and wrist, ultrasonography of the gonads, magnetic resonance imaging). Treatment is directed at both the acute and the long-term consequences of precocious, markedly delayed, or absent pubertal development.

CONCLUSIONS

Disorders of pubertal development should be recognized early, correctly diagnosed by a pediatric endocrinologist, and appropriately treated.

Endocrinology of male puberty

PURPOSE OF REVIEW

To review recent information leading to a better understanding of the endocrinology of male puberty, including information from earlier stages of life.

RECENT FINDINGS

Differences in relative levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the neonatal period have been further described, as well as changes in inhibin B and anti-Müllerian hormone levels. Studies among men with congenital hypogonadotropic hypogonadism suggest a role for the 'minipuberty of infancy' in inhibin B levels. Gonadotropin-releasing hormone analog-stimulated LH levels at the age of puberty may be useful in diagnosing hypogonadotropic hypogonadism. Inhibin B levels are likewise useful in monitoring spermatogenic activity.

SUMMARY

Data from fetal life (men born small for gestational age with evidence of a defect in steroidogenesis, relatively high LH:FSH ratio among very premature boys), neonatal period (attenuated rise of inhibin B after rFSH stimulation among men with congenital hypogonadotropic hypogonadism), and puberty (often demonstrable by LH levels alone, progressive rise of insulin-like factor 3 levels, and decrease of anti-Müllerian hormone levels as a consequence of FSH and LH stimulation), all enhance the understanding of the physiology of puberty.

Idiopathic short stature: definition, epidemiology, and diagnostic evaluation

Idiopathic short stature is a condition in which the height of the individual is more than 2 SD below the corresponding mean height for a given age, sex and population, in whom no identifiable disorder is present. It can be subcategorized into familial and non-familial ISS, and according to pubertal delay. It should be differentiated from dysmorphic syndromes, skeletal dysplasias, short stature secondary to a small birth size (small for gestational age, SGA), and systemic and endocrine diseases. ISS is the diagnostic group that remains after excluding known conditions in short children.