Does constitutional delayed puberty cause segmental disproportion and short stature?

Outcomes and experiences of adults with congenital hypogonadism can inform improvements in the management of delayed puberty

Patients with congenital hypogonadism will encounter many health care professionals during their lives managing their health needs; from antenatal and infantile periods, through childhood and adolescence, into adult life and then old age. The pubertal transition from childhood to adult life raises particular challenges for diagnosis, therapy and psychological support, and patients encounter many pitfalls. Many patients with congenital hypogonadism and delayed or absent puberty are only diagnosed and treated after long diagnostic journeys, and their management across different centres and countries is not well standardised. Here we reconsider the management of pubertal delay, whilst addressing problematic diagnostic issues and highlighting the limitations of historic pubertal induction protocols - from the perspective of both an adult and a paediatric endocrinologist, dealing in our everyday work with the long-term adverse consequences to our hypogonadal patients of an incorrect and/or late diagnosis and treatment in childhood.

Puberty Induction in Adolescent Males: Current Practice

Puberty is a developmental stage characterized by the appearance of secondary sexual characteristics which leads to complete physical, psychosocial, and sexual maturation. The current practice of hormonal therapy to induce puberty in adolescent males is based on published consensus and expert opinion. Evidence-based guidelines on optimal timing and regimen in puberty induction in males are lacking, and this reflects some discrepancies in practice among endocrinologists. It is worth mentioning that the availability of various hormonal products in markets, their different routes of administration, and patients/parents’ preference also have an impact on clinical decisions. This review outlines the current clinical approach to delayed puberty in boys with an emphasis on puberty induction.

Current clinical management of constitutional delay of growth and puberty

BACKGROUND

Constitutional delay of growth and puberty (CDGP) is classified as the most frequent cause of delayed puberty (DP). Finding out the etiology of DP during first evaluation may be a challenge. In details, pediatricians often cannot differentiate CDGP from permanent hypogonadotropic hypogonadism (PHH), with definitive diagnosis of PHH awaiting lack of puberty by age 18 yr. Neverthless, the ability in providing a precise and tempestive diagnosis has important clinical consequences.

MAIN TEXT

A growth failure in adolescents with CDGP may occur until the onset of puberty; after that the growth rate increases with rapidity. Bone age is typically delayed. CDGP is generally a diagnosis of exclusion. Nevertheless, other causes of DP must be evaluated. A family history including timing of puberty in the mother and in the father as well as physical examination may givee information on the cause of DP. Patients with transient delay in hypothalamic-pituitary-gonadal axis maturation due to associated conditions, such as celiac disease, inflammatory bowel diseases, kidney insufficiency and anorexia nervosa, may experience a functional hypogonadotropic hypogonadism. PHH revealing testosterone or estradiol low serum values and reduced FSH and LH levels may be connected to abnormalities in the central nervous system. So, magnetic resonance imaging is required in order to exclude either morphological alterations or neoplasia. If the adolescent with CDGP meets psychological difficulties, treatment is recommended.

CONCLUSION

Even if CDGP is considered a variant of normal growth rather than a disease, short stature and retarded sexual development may led to psychological problems, sometimes associated to a poor academic performance. A prompt and precise diagnosis has an important clinical outcome. Aim of this mini-review is throwing light on management of patients with CDGP, emphasizing the adolescent diagnosis and trying to answer all questions from paediatricians.

Genetics of pubertal timing

Puberty marks the end of childhood and is a period when individuals undergo physiological and psychological changes to achieve sexual maturation and fertility. The onset of puberty is first detected as an increase in pulsatile secretion of gonadotropin-releasing hormone (GnRH). Pubertal onset is regulated by genetic, nutritional, environmental, and socio-economic factors. Disturbances affecting pubertal timing result in adverse health conditions later in life. Human genetic studies show that around 50-80% of the variation in pubertal onset is genetically determined. The genetic control of pubertal timing has been a field of active investigation in attempt to better understand the neuroendocrine control of this relevant period of life. Large populational studies and patient cohort-based studies have provided insights into the genetic regulation of pubertal onset. In this review, we discuss these discoveries and discuss potential mechanisms for how implicated genes may affect pubertal timing.

Sitting Height to Standing Height Ratio Reference Charts for Children in the United States

OBJECTIVE

To create reference charts for sitting height to standing height ratio (SitHt/Ht) for children in the US, and to describe the trajectory of SitHt/Ht during puberty.

STUDY DESIGN

This was a cross-sectional study using data from the 1988-1994 National Health and Nutrition Examination Survey III, a strategic random sample of the US population. Comparison between non-Hispanic White (NHW), non-Hispanic Black (NHB) and Mexican American groups was performed by ANOVA to determine if a single population reference chart could be used. ANOVA was used to compare SitHt/Ht in pre-, early, and late puberty.

RESULTS

NHANES III recorded sitting height and standing height measurements in 9569 children aged 2-18 years of NHW (n = 2715), NHB (n = 3336), and Mexican American (n = 3518) ancestry. NHB children had lower SitHt/Ht than NHW and Mexican American children throughout childhood (P < .001). In both sexes, the SitHt/Ht decreased from prepuberty to early puberty and increased in late puberty. Sex-specific percentile charts of SitHt/Ht vs age were generated for NHB and for NHW and Mexican American youth combined.

CONCLUSIONS

SitHt/Ht assessment can detect disproportionate short stature in children with skeletal dysplasia, but age-, sex-, and population-specific reference charts are required to interpret this measurement. NHB children in the US have significantly lower SitHt/Ht than other children, which adds complexity to interpretation. We recommend the use of standardized ancestry-specific reference charts in screening for skeletal dysplasias and have developed such charts in this study.

Testosterone Therapy in Adolescent Boys: The Need for a Structured Approach

BACKGROUND

In adolescents, testosterone may have several effects including promotion of secondary sexual characteristics and pubertal growth, attainment of optimal muscle mass and peak bone mass, optimization of the metabolic profile, and psychosocial maturation and well-being.

SUMMARY

Testosterone therapy is a cornerstone of the management of hypogonadism in boys. Since the initial report of the chemical synthesis of testosterone, several formulations have continued to develop, and although many of these have been used in boys, none of them have been studied in detail in this age group. Given the wide ranging effects of testosterone, the level of evidence for their effects in boys and the heterogeneity of conditions that lead to early-onset hypogonadism, a standardized protocol for monitoring testosterone replacement in this age group is needed. Key Messages: In this review, we focus on the perceived benefits of androgen replacement in boys affected by pubertal delay and highlight the need to improve the health monitoring of boys who receive androgen replacement therapy, proposing different approaches based on the underlying pathophysiology.

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.

Long-Term Skeletal Disproportion in Childhood-Onset Crohn's Disease

BACKGROUND

It is unclear whether Crohn's disease (CD) is associated with skeletal disproportion in adulthood.

METHODS

Height (Ht), sitting height (SHt) and leg length were studied in 44 children (male: 22), 23 adults (male: 10) with childhood-onset (CO) CD and 26 adults (male: 9) with adult-onset (AO) CD with a median (range) age of 13.7 (10, 17.3), 21.5 (18, 32) and 31.0 (22, 40) years, respectively.

RESULTS

Adults with CO-CD had a median Ht standard deviation score (SDS) of -0.9 (-2.3, 0.0) compared to 0.6 (-0.8, 1.0) in those with AO-CD (p < 0.05). Compared to a normal population, men, but not women, with CO-CD also had lower median SHt SDS at -1.1 (2.5, -0.5) (p < 0.05). The expected positive association that is normally found between leg length and SHt SDS was not evident in the adults with CO-CD.

CONCLUSION

Short stature in adults with CO-CD is more pronounced in men and may be associated with poor spinal growth.

Management of hypogonadism from birth to adolescence

Management of patients with hypogonadism is dependent on the underlying cause. Whilst functional hypogonadism presenting as delayed puberty in adolescence is relatively common, permanent hypogonadism presenting in infancy or adolescence is unusual. The main differential diagnoses of delayed puberty include self-limited delayed puberty (DP), idiopathic hypogonadotropic hypogonadism (IHH) and hypergonadotropic hypogonadism. Treatment of self-limited DP involves expectant observation or short courses of low dose sex steroid supplementation. More complex and involved management is required in permanent hypogonadism to achieve both development of secondary sexual characteristics and to maximize the potential for fertility. This review will cover the options for management involving sex steroid or gonadotropin therapy, with discussion of benefits, limitations and specific considerations of the different treatment options.

Adult Consequences of Self-Limited Delayed Puberty

Delayed puberty is a common condition defined as the lack of sexual maturation by an age ≥2 SD above the population mean. In the absence of an identified underlying cause, the condition is usually self-limited. Although self-limited delayed puberty is largely believed to be a benign developmental variant with no long-term consequences, several studies have suggested that delayed puberty may in fact have both harmful and protective effects on various adult health outcomes. In particular, height and bone mineral density have been shown to be compromised in some studies of adults with a history of delayed puberty. Delayed puberty may also negatively affect adult psychosocial functioning and educational achievement, and individuals with a history of delayed puberty carry a higher risk for metabolic and cardiovascular disorders. In contrast, a history of delayed puberty appears to be protective for breast and endometrial cancer in women and for testicular cancer in men. Most studies on adult outcomes of self-limited delayed puberty have been in small series with significant variability in outcome measures and study criteria. In this article, we review potential medical and psychosocial issues for adults with a history of self-limited delayed puberty, discuss potential mechanisms underlying these issues, and identify gaps in knowledge and directions for future research.

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.

Targeted resequencing of the pericentromere of chromosome 2 linked to constitutional delay of growth and puberty

Constitutional delay of growth and puberty (CDGP) is the most common cause of pubertal delay. CDGP is defined as the proportion of the normal population who experience pubertal onset at least 2 SD later than the population mean, representing 2.3% of all adolescents. While adolescents with CDGP spontaneously enter puberty, they are at risk for short stature, decreased bone mineral density, and psychosocial problems. Genetic factors contribute heavily to the timing of puberty, but the vast majority of CDGP cases remain biologically unexplained, and there is no definitive test to distinguish CDGP from pathological absence of puberty during adolescence. Recently, we published a study identifying significant linkage between a locus at the pericentromeric region of chromosome 2 (chr 2) and CDGP in Finnish families. To investigate this region for causal variation, we sequenced chr 2 between the genomic coordinates of 79-124 Mb (genome build GRCh37) in the proband and affected parent of the 13 families contributing most to this linkage signal. One gene, DNAH6, harbored 6 protein-altering low-frequency variants (< 6% in the Finnish population) in 10 of the CDGP probands. We sequenced an additional 135 unrelated Finnish CDGP subjects and utilized the unique Sequencing Initiative Suomi (SISu) population reference exome set to show that while 5 of these variants were present in the CDGP set, they were also present in the Finnish population at similar frequencies. Additional variants in the targeted region could not be prioritized for follow-up, possibly due to gaps in sequencing coverage or lack of functional knowledge of non-genic genomic regions. Thus, despite having a well-characterized sample collection from a genetically homogeneous population with a large population-based reference sequence dataset, we were unable to pinpoint variation in the linked region predisposing delayed puberty. This study highlights the difficulties of detecting genetic variants under linkage regions for complex traits and suggests that advancements in annotation of gene function and regulatory regions of the genome will be critical for solving the genetic background of complex phenotypes like CDGP.

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.

Aromatase inhibitors in pediatrics

Aromatase, an enzyme located in the endoplasmic reticulum of estrogen-producing cells, catalyzes the rate-limiting step in the conversion of androgens to estrogens in many tissues. The clinical features of patients with defects in CYP19A1, the gene encoding aromatase, have revealed a major role for this enzyme in epiphyseal plate closure, which has promoted interest in the use of inhibitors of aromatase to improve adult height. The availability of the selective aromatase inhibitors letrozole and anastrozole--currently approved as adjuvant therapy for breast cancer--have stimulated off-label use of aromatase inhibitors in pediatrics for the following conditions: hyperestrogenism, such as aromatase excess syndrome, Peutz-Jeghers syndrome, McCune-Albright syndrome and functional follicular ovarian cysts; hyperandrogenism, for example, testotoxicosis (also known as familial male-limited precocious puberty) and congenital adrenal hyperplasia; pubertal gynecomastia; and short stature and/or pubertal delay in boys. Current data suggest that aromatase inhibitors are probably effective in the treatment of patients with aromatase excess syndrome or testotoxicosis, partially effective in Peutz-Jeghers and McCune-Albright syndrome, but probably ineffective in gynecomastia. Insufficient data are available in patients with congenital adrenal hyperplasia or functional ovarian cysts. Although aromatase inhibitors appear effective in increasing adult height of boys with short stature and/or pubertal delay, safety concerns, including vertebral deformities, a decrease in serum HDL cholesterol levels and increase of erythrocytosis, are reasons for caution.

Androgen therapy for delayed male puberty

PURPOSE OF REVIEW

Delayed puberty in men is a commonly presenting problem to paediatricians and an understanding of the available evidence on cause, treatments and outcomes is important to guide practice.

RECENT FINDINGS

Understanding of the regulation of the onset of puberty is gradually unfolding, although the genetic factors that dictate the timing of puberty in individuals and families remain poorly elucidated. Mutations and polymorphisms in candidate genes are being actively studied and it is likely that there is significant overlap between traditional diagnostic categories. Also, environmental endocrine disruptors may interact with the genetic regulation of puberty. Delayed puberty may not always be a benign condition, with increased risks of failing to achieve target height, adverse psychological and educational consequences, delayed sexual and psychosocial integration into society and effects on skeletal proportions and bone mass reported. Appropriate evaluation and follow-up is needed to guide clinical practice, particularly to distinguish constitutional delay in growth and puberty from that associated with other medical disease or permanent disorders.

SUMMARY

In milder cases of delayed puberty, treatment is often not required; however, considerable evidence exists for the efficacy and safety of short courses of low-dose testosterone therapy for appropriately selected individuals. This treatment is associated with high levels of patient satisfaction. There is not yet sufficient evidence for the routine use of other therapies (e.g. growth hormone, aromatase inhibitors) for constitutional delay in growth and puberty and better characterization of cause may lead to more targeted individual therapy.

The age of puberty determines sexual dimorphism in bone structure: a male/female co-twin control study

BACKGROUND

Taller stature and larger bone size in males are attributed to more rapid growth than in females. However, comparing sexes of the same age mismatches by pubertal stage, so males will be less mature than females. Comparing sexes of the same pubertal stage mismatches by age, so males will be older than females.

OBJECTIVE

We hypothesized that sex differences in stature and bone structure are the result of sex differences in the duration but not the rate of prepubertal and pubertal growth.

METHODS

We measured bone dimensions in 90 male/female co-twin pairs aged 7-18 yr using anthropometry and dual x-ray absorptiometry. Forty-two pairs had follow-up assessments. Within-pair differences were expressed as a percentage of the pair mean.

RESULTS

Thirty percent of the 1-1.5 sd sex difference in bone widths and midfemur bending strength observed in 11 postpubertal pairs was present in 43 prepubertal pairs. In prepubertal pairs, annual growth in leg length was about 1.5 times truncal growth, but neither rate differed by sex. During puberty, truncal growth in both sexes was higher than before puberty but did not differ by sex. The longer period of pre- and intrapubertal growth in males produced most of the sex difference in bone morphology observed in postpubertal twins.

CONCLUSION

Sex differences in bone morphology are the result of the later onset of puberty in males, not more rapid growth. Differences in bone widths are partly established before puberty.

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

BACKGROUND/AIMS

In some adolescents with constitutional delay of growth and puberty (CDGP), the reduction in relative height (height SDs) starts already in childhood, before puberty. Some subjects with CDGP do not reach their target height (TH). We investigated whether early height SD reduction or testosterone treatment in low doses (1-2 mg/kg/month) influence final height (FH).

METHODS

The growth of 70 adult men with a history of CDGP was investigated. 31 subjects (13 treated with testosterone) had progressive height SD reduction between 3 and 9 years, and in 39 (17 treated with testosterone) no such reduction was seen.

RESULTS

In untreated subjects without early height SD reduction, FH was closer to TH than in those with such reduction (FH - TH 0.05 +/- 0.94 vs. -0.63 +/- 0.50 SD, p = 0.009). FH - TH did not differ between the testosterone-treated and untreated subjects in the group with early height SD reduction (FH - TH -0.36 +/- 0.48 vs. -0.63 +/- 0.50 SD, p = 0.15), nor in the group without such reduction (FH - TH -0.08 +/- 0.70 vs. 0.05 +/- 0.94 SD, p = 0.64).

CONCLUSION

Subjects with early height SD reduction do not attain FH consistent with their genetic height potential, whereas those without such reduction do. Treatment with low doses of testosterone does not adversely affect FH.

Bone width is correlated positively with the upper to the lower segment ratio in elderly men--the MINOS study

Before puberty, limbs grow more rapidly than the spine. During puberty, lengthening of the spine and increase in bone width accelerate. Correlation of parameters with lengths of the upper and lower segments and with the upper/lower segment ratio may indicate the period of growth critical for their determination. We assessed the association of bone mineral and width with the upper/lower segment ratio in 542 elderly men from the MINOS cohort. Areal bone mineral density (aBMD) was measured at the lumbar spine and right hip using pencil-beam dual-energy X-ray absorptiometry and at the distal forearm using single energy X-ray absorptiometry. Upper/lower segment ratio correlated positively with bone mineral content (BMC), aBMD and width of third lumbar vertebra (L3), femoral neck and distal radius. Men in the highest quartile of the upper/lower segment ratio had larger bones by 2.5 to 5.0% (0.3-0.4 SD, p<0.02-0.002) compared with the lowest quartile. Bone width correlated more strongly with the upper segment length than with that of the lower one. Volumetric BMD (vBMD) did not correlate with the upper/lower segment ratio nor with the lengths of the body segments. At the femoral neck and distal radius, men in the highest quartile of the upper/lower segment ratio had higher estimated cortical thickness (5.3%, 0.41 SD, p<0.01 and 4.0%, 0.31 SD, p<0.03), bigger cortical area (8.0%, 0.54 SD and 6.8%, 0.52 SD, p<0.0001) and higher estimated bending strength (9.3 to 13.3%, 0.46 to 0.54 SD, p<0.0001). Elderly men with the higher upper/lower segment ratio had higher BMC and bending strength because they had wider bones, not higher vBMD. The bone size correlated positively with the length of the upper segment, not negatively with that of the lower segment. Our data may suggest an important role of pubertal growth for both bone width and strength in men but do not establish the determinants of this association. Given methodological limitations, these results need to be confirmed in a younger and more representative group of men.

Use of aromatase inhibitors to increase final height

During puberty in both sexes, the mechanism involved in epiphyseal fusion is mediated by the action of estrogen through a cascade of events including proliferation, differentiation, and apoptosis of chondrocytes. The enzyme P450 aromatase catalyzes the aromatization of C19 androgens (androstenedione and testosterone) to C18 estrogens (estrone and estradiol). Inhibition of estrogen action by aromatase inhibitors (AIs) appears to decelerate the process of growth plate fusion, and thus AIs may be used therapeutically to increase adult height. The clinical experience with AIs in the pediatric setting is limited to testolactone, fadrozole, letrozole, and anastrozole. Testolactone, a nonselective steroidal AI, has been used successfully as an adjunct to antiandrogen and gonadotropin-releasing hormone analogue (GnRHa), therapy for children with familial male-limited precocious puberty (FMPP) and congenital adrenal hyperplasia (CAH), and with some success in girls with McCune-Albright syndrome. The limitations of testolactone include its relatively low potency and the need for frequent dosing. Results of a randomized placebo-controlled trial in boys with delayed puberty treated with letrozole, a selective nonsteroidal AI, found that boys treated with letrozole + testosterone experienced delayed bone maturation and good growth response and achieved an increase in predicted adult height. In this study, only minor differences in bone density were seen between the placebo and letrozole treatment groups, both of which were receiving concomitant testosterone therapy. No adverse effects on testis size or inhibin B concentration were noted. The therapeutic value of AIs in growth promotion now remains to be substantiated in future controlled clinical trials.

Treatment with the aromatase inhibitor letrozole during adolescence increases near-final height in boys with constitutional delay of puberty

OBJECTIVE

We investigated whether inhibition of oestrogen biosynthesis with the aromatase inhibitor, letrozole, during adolescence improves near-final height in boys with constitutional delay of puberty.

PATIENTS AND METHODS

Seventeen boys with constitutional delay of puberty were randomized to receive testosterone (T) enanthate (1 mg/kg i.m.) every 4 weeks for 6 months in combination with placebo (Pl, n = 8), or the aromatase inhibitor letrozole (Lz, 2.5 mg/day orally) (n = 9), for 12 months. After treatment, patients were followed up until near-final height. Height discrepancy was calculated as near-final height minus mid-parental target height.

MEASUREMENTS

The primary end point was the difference in near-final height between the groups treated either with T + Pl or T + Lz. Secondarily, height discrepancy and gain in height standard deviation score (SDS) were analysed in both groups.

RESULTS

Boys treated with T + Lz reached a higher mean near-final height than did boys on T + Pl (175.8 vs. 169.1 cm, respectively, P = 0.04). In T + Lz-treated boys, mean near-final height did not differ from their mid-parental target height (175.8 vs. 177.1 cm, P = 0.38), whereas in T + Pl-treated boys, mean near-final height was lower than mid-parental target height (169.1 vs. 173.9 cm, P = 0.007). T + Lz-treated boys had a greater increment in height SDS over the pretreatment height SDS than T + Pl-treated boys (+1.4 SDS vs.+0.8 SDS, P = 0.03).

CONCLUSIONS

Our findings indicate that in adolescent boys an increase in adult height can be attained by use of aromatase inhibitors.

Constitutional delay of growth and puberty: from presentation to final height

This retrospective study evaluated clinical characteristics of patients with constitutional delay of growth and puberty (CDGP) at presentation, during puberty and at final height. The records of 151 children (105 boys, 46 girls) with CDGP were reviewed and the results were evaluated with respect to findings in healthy Turkish schoolchildren. CDGP was twice as frequent in boys as in girls. Height and weight deficit and short sitting height of the children were evident at presentation and continued up to final height. Mean age of onset of puberty was retarded by 2.5 years in girls and by 3 years in boys. The time between onset of puberty and pubertal growth spurt was shorter in both girls and boys than in the controls. Peak growth velocity was compromised in both girls and boys. Forty-one patients (30 boys, 11 girls) reached final height (FH). Mean FH was shorter than both target height and predicted adult height. The Bayley-Pinneau method was found to be a better predictor of FH than either the Tanner-Whitehouse method or target height. FH also showed correlation with the father's height. There was no effect of testosterone treatment on final height. Height deficit at onset of puberty, shorter duration between onset of puberty and pubertal growth spurt, compromised peak growth velocity and short upper segment due to delayed puberty, are findings which may explain the decreased final height of children with CDGP.

Novel treatment of short stature with aromatase inhibitors

Estrogens have an essential role in the regulation of bone maturation and importantly in the closure of growth plates in both sexes. This prospective, randomized, placebo-controlled study was undertaken to evaluate whether suppression of estrogen synthesis in pubertal boys delays bone maturation and ultimately results in increased adult height. A total of 23 boys with constitutional delay of puberty (CDP) received a conventional, low-dose testosterone treatment for inducing progression of puberty. Eleven of these 23 boys were randomized to receive a specific and potent P450-aromatase inhibitor, letrozole, for suppression of estrogen action, and 12 boys were randomized to receive placebo. Estradiol concentrations in the letrozole-treated boys remained at the pretreatment level during the administration of letrozole, whereas the concentrations increased during the treatment with testosterone alone and during spontaneous progression of puberty. Testosterone concentrations increased in all groups, but during the letrozole treatment, the increase was more than fivefold higher than in the group treated with testosterone alone. The inhibition of estrogen synthesis delayed bone maturation. The slower bone maturation in the boys treated with testosterone and letrozole, despite higher androgen concentrations, than in the boys treated with testosterone indicate that estrogens are more important than androgens in regulation of bone maturation in pubertal boys. During the 18 months follow-up, an increase of 5.1 cm in predicted adult height was observed in the boys who received testosterone and letrozole, but no change was seen in the boys who received testosterone alone or in the untreated boys. This finding indicates that an increase in adult height can be attained in growing adolescent boys by inhibiting of estrogen action.

A specific aromatase inhibitor and potential increase in adult height in boys with delayed puberty: a randomised controlled trial

BACKGROUND

The role of oestrogens in the closure of growth plates in both sexes is unequivocal. We postulated that inhibition of oestrogen synthesis in boys with delayed puberty would delay maturation of the growth plates and ultimately result in increased adult height.

METHODS

We did a randomised, double-blind, placebo-controlled study in which we treated boys with constitutional delay of puberty with testosterone and placebo, or testosterone and letrozole. Boys who decided to wait for the spontaneous progression of puberty without medical intervention composed the untreated group.

FINDINGS

Letrozole effectively inhibited oestrogen synthesis and delayed bone maturation. Progression of bone maturation was slower in the letrozole group than in the placebo group. In 18 months, bone age had advanced 1.1 (SD 0.8) years in the untreated group and 1.7 (0.9) years in the group treated with testosterone and placebo, but only 0.9 (0.6) years in the letrozole group (p=0.03 between the treatment groups). Predicted adult height did not change significantly in the untreated group and in the placebo group, whereas in the group treated with letrozole the increase was 5.1 (3.7) cm (p=0.004).

INTERPRETATIONS

Our findings suggest that if oestrogen action is inhibited in growing adolescents, adult height will increase. This finding provides a rationale for studies that aim to delay bone maturation in several growth disorders.

Age at menarche and cortical bone geometry in premenopausal women

Previous studies have suggested that the timing of puberty might have an impact on the adult skeleton. What composite of bone structure could be affected by the timing of puberty is unknown at present. In this study, we evaluated the relationship between age at menarche and bone cortex geometry at the distal radius. Using peripheral quantitative computed tomography, we determined total area of the radial cross section, cortical bone area, periosteal cortical perimeter, endosteal cortical perimeter, and cortical width in 169 healthy premenopausal women aged 40-45 years. When stratified according to age at menarche (early, <12 years In = 22]; intermediate, 12-14 years [n = 118]; late, >14 years [n = 29]), only endosteal cortical perimeter varied significantly between the groups (p = 0.02, by analysis of variance), the mean value being 10% higher in the late compared to the early menarche group. However, weight and body mass index also exhibited significant variations between groups. After adjustment for weight the differences in endosteal cortical perimeter remained significant (p = 0.03). In multiple regression analysis, endosteal cortical perimeter was the only parameter of cortex geometry, which was independently associated with age at menarche. In a model including height and weight, age at menarche explained about 2% of the variability in endosteal cortical perimeter (p = 0.04). These data suggest that the bone marrow cavity of the distal radius may be slightly larger when puberty occurs later. Whether this marginal effect influences fracture risk in later life appears questionable.

Comparison of final heights of growth hormone-treated vs. untreated children with idiopathic growth failure

We measured adult heights (Ht) of 94 healthy GH-sufficient children (peak GH > 10 ng/mL, polyclonal RIA) whose Ht at presentation were more than 2 SD below the mean for chronological age, with normal weight-to-Ht ratios, normal body proportions, and pathologic growth velocity for chronological age. Group 1 (n 36, 6 females) received standardized doses (0.3 mg/kg x week) of GH (mean duration = 41 months), while group 2 (n = 58, 17 females) received no treatment. Our conclusion was that the mean final Ht SD score in the GH-treated group (-1.5) was significantly greater than in the untreated group (-2.1); P < .001. Genetic predisposition to short stature was evident in both groups: the midparental Ht SD score was -1.1 in the treated and -1.0 in the untreated group. Midparental Ht was met or exceeded by 42% of the GH-treated group but only 15% of the untreated group. Final Ht was not significantly different from predicted Ht, except from GH-treated girls, who exceeded their predicted Ht. Although the mean Ht gains (6.8 cm in girls and 3 cm in boys) were modest and variable, GH treatment provided significantly better Ht outcomes for the majority of children with idiopathic growth failure.

Growth of Pakistani children in relation to the 1990 growth standards

This study was designed to compare the growth of Pakistani schoolchildren in the UK with the 1990 UK growth standards. Measurements of height, weight, and sitting height were performed on 785 Pakistani schoolchildren aged 5-14 years with the mean values for each age and sex being plotted on the UK growth standards. The results were expressed as SD scores relative to the 1990 reference data. The mean height for the boys was only 0.2 SD scores below the mean for the new growth standards with the mean height for the girls being 0.4 SD scores below the mean. The mean values for weight and body mass index were 0.3 and 0.5 SD scores less than the mean for boys and girls respectively. This study demonstrates that the growth of Pakistani schoolchildren in the UK is comparable to the 1990 UK growth standards with only minor differences. It is not safe to assume that short stature or low body weight in a Pakistani child is due to his or her ethnic background.

Final height outcome in both untreated and testosterone-treated boys with constitutional delay of growth and puberty

The present retrospective study is based on a historical follow-up of 49 boys with constitutional delay of growth and puberty (CDGP) who went into puberty spontaneously (27 cases) or induced by depotestosterone treatment, 50 mg/ month for 6 months (22 cases). At the time of puberty the two groups of boys were similar in bone age, height deficiency, target height (TH) and had similar predicted final heights (FH). Their FH was measured and compared with TH calculated from measured parents' heights. FH did not significantly differ between the untreated boys and those treated. In the two groups of patients FH was similar and corresponded to both TH and height predicted at puberty onset. This study confirms that most boys with CDGP spontaneously attain a FH within the target range (24/27 cases). A short-term and low dose course of depotestosterone can be used without adverse effects on FH. The Bayley-Pinneau method can be generally considered accurate for predicting FH in CDGP, although significant discrepancies between FH and predicted height have been recorded in a fair number of both untreated and treated boys.

Growth and endocrine sequelae of craniopharyngioma

The growth and endocrine sequelae of 75 children (33 girls and 42 boys) with craniopharyngioma, treated from 1973 to 1994, were studied by retrospective review and by follow up assessment in 66 survivors, with a mean time from initial surgery of 6.7 years (range 1.5 to 19.8 years). Although infrequently complained of, 71% of patients had symptoms to suggest an endocrinopathy at diagnosis. After surgery, multiple endocrinopathies were almost universal, such that 75% of children had panhypopituitarism at follow up. Hypoadrenal crises in association with intercurrent illness contributed significantly to morbidity and mortality, as did the metabolic consequences of concomitant antidiuretic hormone (ADH) insufficiency and absent thirst. Final height in 25 patients was significantly below genetic target height, particularly in the girls, with loss of height potential occurring during the pubertal years. The endocrine morbidity associated with craniopharyngioma and its treatment remains high but manageable with appropriate hormone replacement. However, the combination of ADH insufficiency and an impaired sense of thirst following aggressive surgery and severe hypothalamic injury remains one of the most complex management problems.

The effect of prolonged administration of an anabolic steroid (oxandrolone) on growth in boys with constitutionally delayed growth and puberty

Short-term oxandrolone treatment is used to stimulate growth in boys with constitutional delay of growth and puberty (CDGP). Oxandrolone stimulates growth, but a beneficial effect on final height has not been established. In our study, we report the effect of long-term treatment (30-57 months) with oxandrolone in 18 boys with CDGP, compared with nine puberty-matched, untreated controls (group 1). The oxandrolone-treated boys were divided into two groups: four boys who received oxandrolone before onset of puberty (group 2), and 14 boys who started oxandrolone therapy during Tanner stage 2 (group 3). Height standard deviation scores for calender age (HSDSCA) between the three groups of patients at Tanner stage 2 (G2) were not different: -2.86 (SD 0.56) in the controls and -2.60 (SD 0.52) in group 2 and -2.81 (SD 0.59) in group 3. Age at G2 was 15.1 (SD 1.4) years (controls), 14.6 (SD 0.5) years (group 2) and 14.0 (SD 0.9) years (group 3). Height velocity in the time span from G2 to G5 was more pronounced in the oxandrolone-treated boys: 7.7 (SD 0.5) cm/year in group 2 and 7.7 (SD 1.4) cm/year in group 3 versus 5.1 (SD 0.9) cm/year in the controls. Height gain was significantly increased in the oxandrolone treated groups: 25.8 (SD 3.8) in group 2 and 25.2 (SD 3.7) in group 3 versus 19.8 (SD 4.9) in the controls (P < 0.05). Final height did not differ significantly among the three groups: 168.5 (SD 7.0) cm in the controls and 173.0 (SD 4.0) cm in group 2 and 167.8 (SD 5.3) cm in group 3. HSDSCA increased during puberty in all three groups. At final height, HSDSCA (calculated at age = 20 years) was -2.01 (SD 1.05), -1.34 (SD 0.59) and -2.12 (SD 0.79) respectively in groups 1, 2 and 3. An effect of oxandrolone on HSDSCA was not found. Target height was neither reached by the controls nor by the treated groups. Tempo of pubertal development was not different in the three groups, and delta BA/delta CA did not alter after start of oxandrolone treatment in groups 2 and 3.

CONCLUSION

Boys with CDGP may benefit from oxandrolone treatment in terms of increased height gain. Starting treatment before the onset of puberty may be favourable.

Short-term effect of testosterone treatment on reduced bone density in boys with constitutional delay of puberty

We studied bone mineral content (BMC), bone mineral density (BMD), cortical thickness/total width (CT/TW) ratio and cortical area/total area (CA/TA) ratio in boys with constitutional delay of puberty and the effect of short-term testosterone treatment on bone mass. Seventeen boys (age 13.1-15.8 years) who met the family history and the clinical criteria of constitutional delay of puberty were selected and enrolled in the study. All subjects were eating a diet assuring an adequate intake of calories and calcium. A subset of 8 boys (group A) was treated with testosterone depot (100 mg/month x 6 months) while 9 boys (group B) were not. At inclusion, BMC and BMD were reduced in the patients according to their chronological age (BMC -4.04 +/- 1.34 standard deviation scores [SDS]; BMD -2.95 +/- 0.56 SDS), statural age (BMC -1.75 +/- 0.79 SDS; BMD -1.69 +/- 0.78 SDS), and bone age (BMC -1.80 +/- 0.65 SDS; BMD -1.86 +/- 0.68 SDS). No significant differences between the groups were found (group A: BMC 0.480 +/- 0.57 g/cm, BMD 0.488 +/- 0.037 g/cm2, CT/TW ratio 0.43 +/- 0.4, CA/TA ratio 0.68 +/- 0.04; group B: BMC 0.476 +/- 0.060, p = NS vs. group A; BMD 0.491 +/- 0.036 g/cm2, p = NS vs. group A). At 12 months of follow-up, BMC, BMD, CT/TW ratio, and CA/TA ratio significantly increased in group A (BMC 0.70 +/- 0.13 g/cm, delta +41.1 +/- 28.8%, p < 0.003 vs. 0 month; BMD 0.617 +/- 0.082 g/cm2, delta +26.2 +/- 13.6%, p < 0.005 vs. 0 month; CT/TW ratio 0.52 +/- 0.05, delta +20.59 +/- 10.65%, p < 0.001 vs. 0 month; CA/TA ratio 0.77 +/- 0.05 vs. 0 month; CT/TW ratio 13.60 +/- 6.65%, p < 0.004 vs 0 month), but not in group B (BMC: 0.48 +/- 0.05 g/cm; delta +5.1 7.8%, p = NS vs. 00 month; BMD: 0.492 +/- 0.037 g/cm2; delta +0.54 +/- 8.7%, p = NS vs. 0 month; CT/TW ratio 0.44 +/- 0.04, delta +4.04 +/- 6.75%, p = NS vs. 0 month; CA/TA ratio 0.68 +/- 0.05, delta +2.39 +/- 5.90%, p = NS vs. 0 month). We conclude that boys with constitutional delay of puberty have reduced BMC and BMD. The delay in statural and bone ages did not totally account for the decreased bone mass. Testosterone treatment for 6 months significantly increased BMC, BMD, CT/TW ratio, and CA/TA ratio in these patients, but definitive conclusions on the efficacy of the treatment in improving adult bone mass can be drawn only when our patients reach early childhood.

Predictive factors in the determination of final height in boys with constitutional delay of growth and puberty

Seventy-eight patients who had constitutional delay of growth and puberty were included in a retrospective study to determine whether, at the time of first evaluation, any predictive features could suggest final height outcome. Mean chronologic age was 14.3 years (range, 12 to 18 years), and all were either prepubertal or in an early stage of pubertal maturation (4 ml testicular volume). Initial mean (+/- SD) height standard deviation score was -2.74 (+/- 0.71); 85% had a relatively short spine compared with subischial leg length. Mean (+/- SD) growth rate was 4.8 (+/- 1.6) cm/year, and epiphyseal maturation was delayed by 2.4 (+/- 1) years. Sixteen boys were treated with a sustained-action preparation of testosterone (50 mg monthly for 3 to 4 months), six with oxandrolone (1.25 mg daily for a mean of 4 months), and one with both drugs in sequence. At final height attainment, 58% of the boys failed to achieve their full genetic potential; among the remaining 42%, only 0.7% attained a final height above corrected mid-parental height. The relative disproportion between the segments had no significant change at final height attainment. Regression analysis showed that final height impairment (the difference between mid-parental height and final height) was negatively influenced by standing height and growth velocity when initially evaluated and positively by the degree of segmental body proportion; that is, patients who were taller, were growing at a faster rate, and who had a major degree of segmental body disproportion with a short spine and long leg length attained a final height closer to their mid-parental height, irrespective of the degree of delayed epiphyseal maturation. Neither testosterone nor oxandrolone administered during early puberty modified final height attainment or segmental proportion. We conclude that a late onset in the timing of puberty seems to be deleterious to spinal growth and consequently to final height attainment. An alternative diagnosis should be sought among patients with features of constitutional delay of growth and puberty who do not have a significant degree of body disproportion. In these patients, as well as in those who are extremely short, who have a poor growth rate, or who have an unfavorable genetic potential, an alternative therapeutic approach may be required.

Adult height exceeding target height in a patient with congenital panhypopituitarism diagnosed after the age of 25 years

This case report concerns a prepubertal patient (height 148.7 cm) with congenital anterior panhypopituitarism diagnosed at the chronological age of 25.2 years (bone age 12.5). In spite of his advanced age on initiation of hormonal replacement therapy this patient achieved an adult height (172.8 cm), exceeding those of his father and brothers, because of his markedly delayed bone age. This satisfactory height outcome confirms that final height in hypopituitarism depends on both height at onset of puberty and height with respect to bone age but not chronological age at initiation of growth hormone treatment.