Changes in Adrenal Androgens During Puberty Suppression and Gender-Affirming Hormone Treatment in Adolescents With Gender Dysphoria.

INTRODUCTION: Gender-affirming hormone treatment is known to affect adrenal androgen levels in adult individuals with gender dysphoria (GD). This may be clinically relevant because the adrenal gland plays a critical role in many different metabolic processes. AIM: This study aims to assess the effects of gonadotropin-releasing hormone analogs (GnRHa) treatment and gender-affirming hormone treatment on adrenal androgen levels in adolescents with GD. METHODS: In this prospective study, dehydroepiandrosterone-sulfate (DHEAS) and androstenedione values were measured every 6 months during 2 years of GnRHa treatment only, and 2 years of GnRHa combined with gender-affirming hormone treatment (estradiol or testosterone) in 73 transgirls and 54 transboys. To determine trends in adrenal androgen levels a linear mixed model was used to approximate androgen levels. MAIN OUTCOME MEASURES: DHEAS and androstenedione levels were the main outcome measures. RESULTS: DHEAS levels rose in transboys during GnRHa treatment, which may represent the normal increase during adolescence. In transgirls no change in DHEAS levels during GnRHa treatment was found. Gender-affirming hormone treatment did not affect DHEAS levels in either sex. In transboys androstenedione levels decreased during the first year of GnRHa treatment, which may reflect reduced ovarian androstenedione synthesis, and rose during the first year of gender-affirming hormone treatment, possibly due to conversion of administered testosterone. In transgirls androstenedione levels did not change during either GnRHa or gender-affirming hormone treatment. CLINICAL IMPLICATIONS: No deleterious effects of treatment on adrenal androgen levels were found during approximately 4 years of follow-up. STRENGTHS & LIMITATIONS: This is one of the largest cohort of adolescents with GD, treated using a uniform protocol, with standardized follow-up. The lack of a control group is a limitation. CONCLUSION: The changes in androstenedione levels during GnRHa and gender-affirming hormone treatment in transboys may not be of adrenal origin. The absence of changes in androstenedione levels in transgirls or DHEAS levels in either sex during gender-affirming hormone treatment suggests that gender-affirming hormone treatment does not significantly affect adrenal androgen production. Schagen SEE, Lustenhouwer P, Cohen-Kettenis PT, et al. Changes in Adrenal Androgens During Puberty Suppression and Gender-Affirming Hormone Treatment in Adolescents With Gender Dysphoria. J Sex Med 2018;15:1357-1363.

Efficacy and Safety of Gonadotropin-Releasing Hormone Agonist Treatment to Suppress Puberty in Gender Dysphoric Adolescents.

INTRODUCTION: Puberty suppression using gonadotropin-releasing hormone agonists (GnRHas) is recommended by current guidelines as the treatment of choice for gender dysphoric adolescents. Although GnRHas have long been used to treat precocious puberty, there are few data on the efficacy and safety in gender dysphoric adolescents. Therefore, the Endocrine Society guideline recommends frequent monitoring of gonadotropins, sex steroids, and renal and liver function. AIM: To evaluate the efficacy and safety of GnRHa treatment to suppress puberty in gender dysphoric adolescents. METHODS: Forty-nine male-to-female and 67 female-to-male gender dysphoric adolescents treated with triptorelin were included in the analysis. MAIN OUTCOME MEASURES: Physical examination, including assessment of Tanner stage, took place every 3 months and blood samples were drawn at 0, 3, and 6 months and then every 6 months. Body composition was evaluated using dual energy x-ray absorptiometry. RESULTS: GnRHa treatment caused a decrease in testicular volume in 43 of 49 male-to-female subjects. In one of four female-to-male subjects who presented at Tanner breast stage 2, breast development completely regressed. Gonadotropins and sex steroid levels were suppressed within 3 months. Treatment did not have to be adjusted because of insufficient suppression in any subject. No sustained abnormalities of liver enzymes or creatinine were encountered. Alkaline phosphatase decreased, probably related to a slower growth velocity, because height SD score decreased in boys and girls. Lean body mass percentage significantly decreased during the first year of treatment in girls and boys, whereas fat percentage significantly increased. CONCLUSION: Triptorelin effectively suppresses puberty in gender dysphoric adolescents. These data suggest routine monitoring of gonadotropins, sex steroids, creatinine, and liver function is not necessary during treatment with triptorelin. Further studies should evaluate the extent to which changes in height SD score and body composition that occur during GnRHa treatment can be reversed during subsequent cross-sex hormone treatment.

The relationship between moderate-to-vigorous intensity physical activity and insulin resistance, insulin-like growth factor (IGF-1)-system 1, leptin and weight change in healthy women during pregnancy and after delivery.

CONTEXT: Childbearing is considered to be a significant risk factor for developing overweight and obesity. Physical activity might influence weight change via hormonal changes. OBJECTIVE: To test the hypothesis that higher levels of moderate-to-vigorous intensity physical activity (MVPA) are positively associated with maternal insulin sensitivity and reduce IGF-1, IGFBP-3, leptin levels, bodyweight gain/retention and birth weight. METHODS: In healthy nulliparous women, weight measurements were carried out and blood was collected during pregnancy in the 15th, 25th and 35th week, and after delivery at 6, 26 and 52 weeks. At 15 and 35 weeks of pregnancy and 26 weeks postpartum, MVPA was measured using accelerometers. In linear regression models, the relationship between MVPA below or above the median with metabolic and weight outcomes was assessed, adjusted for maternal BMI, age and smoking. RESULTS: Moderate-to-vigorous intensity physical activity (MVPA) decreased significantly during pregnancy, but was very low already in early pregnancy. Insulin resistance and leptin levels increased during pregnancy and decreased significantly after delivery (all P < 0·05). After adjustment, insulin, IGFBP-3 and BMI were significantly lower at 15 weeks of pregnancy in women with MVPA above the median compared to those with MVPA below the median. After 15 weeks of pregnancy, no significant associations were observed between hormonal levels and MVPA. MVPA was neither related to weight retention, nor to birth weight. CONCLUSION: Except in early pregnancy, MPVA was not related to metabolic outcomes. In addition, MVPA during pregnancy was not related to weight retention or birth weight.

New reference charts for testicular volume in Dutch children and adolescents allow the calculation of standard deviation scores.

AIM: Accurate calculations of testicular volume standard deviation (SD) scores are not currently available. We constructed LMS-smoothed age-reference charts for testicular volume in healthy boys. METHODS: The LMS method was used to calculate reference data, based on testicular volumes from ultrasonography and Prader orchidometer of 769 healthy Dutch boys aged 6 months to 19 years. We also explored the association between testicular growth and pubic hair development, and data were compared to orchidometric testicular volumes from the 1997 Dutch nationwide growth study. RESULTS: The LMS-smoothed reference charts showed that no revision of the definition of normal onset of male puberty - from nine to 14 years of age - was warranted. In healthy boys, the pubic hair stage SD scores corresponded with testicular volume SD scores (r = 0.394). However, testes were relatively small for pubic hair stage in Klinefelter's syndrome and relatively large in immunoglobulin superfamily member 1 deficiency syndrome. CONCLUSION: The age-corrected SD scores for testicular volume will aid in the diagnosis and follow-up of abnormalities in the timing and progression of male puberty and in research evaluations. The SD scores can be compared with pubic hair SD scores to identify discrepancies between cell functions that result in relative microorchidism or macroorchidism.

Sex differences in verbal fluency during adolescence: a functional magnetic resonance imaging study in gender dysphoric and control boys and girls.

INTRODUCTION: In the literature, verbal fluency (VF) is generally described as a female-favoring task. Although it is conceivable that this sex difference only evolves during adolescence or adulthood under influence of sex steroids, this has never been investigated in young adolescents. AIM: First, to assess sex differences in VF performance and regional brain activation in adolescents. Second, to determine if untreated transsexual adolescents differ from their sex of birth with regard to VF performance and regional brain activation. METHOD: Twenty-five boys, 26 girls, 8 Male-to-Female transsexual adolescents (MtFs), and 14 Female-to-Male transsexual adolescents (FtMs) were tested in a cross-sectional study, while performing a phonetic and semantic VF task within an MRI scanner. MAIN OUTCOME MEASURES: Functional MRI response during VF task. RESULTS: Boys and girls produced similar amounts of words, but the group MtFs produced significantly more words in the phonetic condition compared to control boys, girls, and FtMs. During the semantic condition, no differences were found. With regard to brain activity, control boys showed more activation in the right Rolandic operculum, a small area adjacent to Broca's area, compared to girls. No significant differences in brain activity were found comparing transsexual adolescents, although sub-threshold activation was found in the right Rolandic operculum indicating a trendwise increase in activation from control girls to FtMs to MtFs to control boys. CONCLUSIONS: The better performance of MtFs is consistent with our expectation that MtFs perform better on female-favoring tasks. Moreover, they produced more words than girls and FtMs. Even though a trendwise linear increase in brain activity between the four groups only approached significance, it may indicate differences in individuals with gender identity disorder compared to their birth sex. Although our findings should thus be interpreted with caution, they suggest a biological basis for both transgender groups performing in-between the two sexes.

Effect of the Go4it multidisciplinary group treatment for obese adolescents on health related quality of life: a randomised controlled trial.

BACKGROUND: We developed a Dutch outpatient multidisciplinary group treatment (Go4it) for obese adolescents, including cognitive behavioural therapy and education on healthy dietary and physical activity behaviour. This study examined the effect of Go4it on Health Related Quality of Life (HRQoL). METHODS: At our outpatient paediatric obesity clinic, obese adolescents (n = 122, 11-18 years) were randomly assigned to 1) Go4it, 7 sessions with an interval of 2 weeks or 2) current regular care consisting of referral to a dietician in the home care setting (controls). Linear mixed model analysis was performed to evaluate the intervention effects on HRQoL at 6 and 18-month follow-ups. HRQoL indicators included the Child Health Questionnaire, the Paediatric Quality of Life Inventory™ Version 4.0 (PedsQL™4.0), and the Body Esteem Scale (BES). RESULTS: In total, 95 adolescents (Go4it 57, controls 38) were included in the current analysis with a mean age of 14.5 ± 1.7 and mean BMI-SDS of 2.9 ± 0.5. At baseline, all participants experienced lower levels of physical and psychosocial well-being compared to a normal weight reference group. At the 18 month follow-up, we found small but beneficial intervention effects on all subscales of the PedsQL™4.0 and BES questionnaires. Two subscales improved significantly; i.e., physical health (between group difference 5.4; 95%CI: 0.3; 10.6), and school functioning (between group difference 7.4; 95%CI: 1.6; 13.2). CONCLUSION: Obese adolescents experienced lower HRQoL than their healthy peers. The Go4it intervention had small beneficial effects on HRQoL compared to the current regular care practices for obese adolescents. TRIAL REGISTRATION: Netherlands Trial Register: ISRCTN27626398, METC number: 05.134 (WMO, monocenter).

Resting-state networks in awake five- to eight-year old children.

During the first 6-7 years of life children undergo a period of major neurocognitive development. Higher-order cognitive functions such as executive control of attention, encoding and retrieving of stored information and goal-directed behavior are present but less developed compared to older individuals. There is only very limited information from functional magnetic resonance imaging (fMRI) studies about the level of organization of functional networks in children in the early school period. In this study we perform continuous resting-state functional connectivity MRI in 5- to 8-year-old children in an awake state to identify and characterize resting-state networks (RSNs). Temporal concatenation independent component analysis (ICA) approach was applied to analyze the data. We identified 14 components consisting of regions known to be involved in visual and auditory processing, motor function, attention control, memory, and the default mode network (DMN). Most networks, in particular those supporting basic motor function and sensory related processing, had a robust functional organization similar to mature adult patterns. In contrast, the DMN and other RSNs involved in higher-order cognitive functions had immature characteristics, revealing incomplete and fragmented patterns indicating less developed functional connectivity. We therefore conclude that the DMN and other RSNs involved in higher order cognitive functioning are detectable, yet in an immature state, at an age when these cognitive abilities are mastered.

Sibling sex ratio and birth order in early-onset gender dysphoric adolescents.

Several sibship-related variables have been studied extensively in sexual orientation research, especially in men. Sibling sex ratio refers to the ratio of brothers to sisters in the aggregate sibships of a group of probands. Birth order refers to the probands' position (e.g., first-born, middle-born, last-born) within their sibships. Fraternal birth order refers to their position among male siblings only. Such research was extended in this study to a large group of early-onset gender dysphoric adolescents. The probands comprised 94 male-to-female and 95 female-to-male gender dysphoric adolescents. The overwhelming majority of these were homosexual or probably prehomosexual. The control group consisted of 875 boys and 914 girls from the TRAILS study. The sibling sex ratio of the gender dysphoric boys was very high (241 brothers per 100 sisters) compared with the expected ratio (106:100). The excess of brothers was more extreme among the probands' older siblings (300:100) than among their younger siblings (195:100). Between-groups comparisons showed that the gender dysphoric boys had significantly more older brothers, and significantly fewer older sisters and younger sisters, than did the control boys. In contrast, the only notable finding for the female groups was that the gender dysphoric girls had significantly fewer total siblings than did the control girls. The results for the male probands were consistent with prior speculations that a high fraternal birth order (i.e., an excess of older brothers) is found in all homosexual male groups, but an elevated sibling sex ratio (usually caused by an additional, smaller excess of younger brothers) is characteristic of gender dysphoric homosexual males. The mechanisms underlying these phenomena remain unknown.

Network analysis of resting state EEG in the developing young brain: structure comes with maturation.

During childhood, brain structure and function changes substantially. Recently, graph theory has been introduced to model connectivity in the brain. Small-world networks, such as the brain, combine optimal properties of both ordered and random networks, i.e., high clustering and short path lengths. We used graph theoretical concepts to examine changes in functional brain networks during normal development in young children. Resting-state eyes-closed electroencephalography (EEG) was recorded (14 channels) from 227 children twice at 5 and 7 years of age. Synchronization likelihood (SL) was calculated in three different frequency bands and between each pair of electrodes to obtain SL-weighted graphs. Mean normalized clustering index, average path length and weight dispersion were calculated to characterize network organization. Repeated measures analysis of variance tested for time and gender effects. For all frequency bands mean SL decreased from 5 to 7 years. Clustering coefficient increased in the alpha band. Path length increased in all frequency bands. Mean normalized weight dispersion decreased in beta band. Girls showed higher synchronization for all frequency bands and a higher mean clustering in alpha and beta bands. The overall decrease in functional connectivity (SL) might reflect pruning of unused synapses and preservation of strong connections resulting in more cost-effective networks. Accordingly, we found increases in average clustering and path length and decreased weight dispersion indicating that normal brain maturation is characterized by a shift from random to more organized small-world functional networks. This developmental process is influenced by gender differences early in development.

Androgen receptor gene CAG repeat polymorphism in longitudinal height and body composition in children and adolescents.

OBJECTIVE: The number of CAG repeats within the CAG repeat polymorphism of the androgen receptor (AR) gene correlates inversely with the transactivation of the receptor. We investigated the relationship between the AR CAG repeat polymorphism and longitudinal growth, puberty and body composition from prepuberty until young adult age. DESIGN: Observational study with repeated measurements. SUBJECTS: Two comparable young Dutch cohorts. The first cohort consisted of 226 subjects. Measurements were performed from 13 until 36 years of age. The second cohort consisted of 244 subjects. Measurements in this cohort were performed from 8 until 14 years of age. MEASUREMENTS: Associations between height, height velocity, weight, BMI, fat mass, fat-free mass and pubertal development and CAG repeat length were measured. RESULTS: Height-standard deviation scores (SDS) were inversely associated with AR CAG repeat length in boys at young, prepubertal and early pubertal age. This association diminishes in the following years and completely disappears after the age of 16 years. No associations were found with pubertal stage or any of the other parameters for body composition. CONCLUSIONS: AR CAG repeat length is inversely associated with longitudinal height in young boys, before the onset of puberty. During puberty, these differences disappear, possibly overruled by a strongly developing hypothalamic-pituitary-gonadal axis.

Puberty suppression in a gender-dysphoric adolescent: a 22-year follow-up.

Puberty suppression by means of gonadotropin releasing hormone (GnRH) analogs is considered a diagnostic aid in gender dysphoric adolescents. However, there are also concerns about potential risks, such as poor outcome or post-surgical regret, adverse effects on metabolic and endocrine status, impaired increment of bone mass, and interference with brain development. This case report is on a 22-year follow-up of a female-to-male transsexual, treated with GnRH analogs at 13 years of age and considered eligible for androgen treatment at age 17, and who had gender reassignment surgery at 20 and 22 years of age. At follow-up, he indicated no regrets about his treatment. He was functioning well psychologically, intellectually, and socially; however, he experienced some feelings of sadness about choices he had made in a long-lasting intimate relationship. There were no clinical signs of a negative impact on brain development. He was physically in good health, and metabolic and endocrine parameters were within reference ranges. Bone mineral density was within the normal range for both sexes. His final height was short as compared to Dutch males; however, his body proportions were within normal range. This first report on long-term effects of puberty suppression suggests that negative side effects are limited and that it can be a useful additional tool in the diagnosis and treatment of gender dysphoric adolescents.

Body size of twins compared with siblings and the general population: from birth to late adolescence.

OBJECTIVES: We examined whether and when differences in body size disappear over time and whether twins attain normal final height and body mass index (BMI). STUDY DESIGN: Height, weight, and BMI data of twins at ages 1, 4, and 18 years were compared with data from their nontwin siblings. Second, twin and sibling data were compared with population standards. In addition to height, weight, and BMI, data on body proportions at age 18 years were analyzed. RESULTS: At the age of 18 years, twins were as tall as their siblings but were significantly leaner. Compared with children from the general population, adolescent twins attained the same height and BMI. Birth weight was shown to have a considerable effect on height in adolescent twins. CONCLUSIONS: Twins attained normal final height compared with siblings and children from the general population. No differences in BMI were shown between 18-year-old twins and children from the general population, whereas the siblings of twins had increased BMI values compared with the general population.

Follow-up results on monitoring and discussing health-related quality of life in adolescent diabetes care: benefits do not sustain in routine practice.

OBJECTIVE: We previously demonstrated that adding monitoring and discussion of health-related quality of life (HRQoL) of adolescents with type 1 diabetes to routine periodic consultations positively impacts psychosocial well-being and satisfaction with care. The current study examines whether these positive effects are maintained 1 year after the intervention was terminated and patients received regular care again, with no formal HRQoL assessment. PATIENTS AND METHODS: Forty-one adolescents with type 1 diabetes were followed for 1 year after the initial HRQoL intervention, in which their HRQoL had been assessed and discussed as part of period consultations using the PedsQL. Changes in physical and psychosocial well-being [Child Health Questionnaire-Child Form 87 (CHQ-CF87), diabetes family conflict scale (DFCS), Center for Epidemiological Studies scale for Depression (CES-D)], satisfaction with care [Patients' Evaluation of the Quality of Diabetes (PEQ-D) care], and glycemic control (HbA(1c)) were determined 12 months after the HRQoL intervention had ended. RESULTS: One year after the HRQoL intervention, mean scores on CHQ subscales: behavior (p = 0.001), mental health (p = 0.004), and self-esteem (p < 0.001) had decreased, whereas the family activities subscale remained stable. Adolescents were less satisfied with their care (p = 0.012), and HbA(1c) values had increased significantly 12 months postintervention (p = 0.002). CONCLUSIONS: The beneficial effects of an office-based HRQoL intervention in adolescents with diabetes largely disappear 1 year after withdrawing the HRQoL assessment procedure. This finding underscores the importance of integrating standardized evaluation and discussion of HRQoL in routine care for adolescents with diabetes.

Preparing children with a mock scanner training protocol results in high quality structural and functional MRI scans.

We evaluated the use of a mock scanner training protocol as an alternative for sedation and for preparing young children for (functional) magnetic resonance imaging (MRI). Children with severe mental retardation or developmental disorders were excluded. A group of 90 children (median age 6.5 years, range 3.65-14.5 years) participated in this study. Children were referred to the actual MRI investigation only when they passed the training. We assessed the pass rate of the mock scanner training sessions. In addition, the quality of both structural and functional MRI (fMRI) scans was rated on a semi-quantitative scale. The overall pass rate of the mock scanner training sessions was 85/90. Structural scans of diagnostic quality were obtained in 81/90 children, and fMRI scans with sufficient quality for further analysis were obtained in 30/43 of the children. Even in children under 7 years of age, who are generally sedated, the success rate of structural scans with diagnostic quality was 53/60. FMRI scans with sufficient quality were obtained in 23/36 of the children in this younger age group. The association between age and proportion of children with fMRI scans of sufficient quality was not statistically significant. We conclude that a mock MRI scanner training protocol can be useful to prepare children for a diagnostic MRI scan. It may reduce the need for sedation in young children undergoing MRI. Our protocol is also effective in preparing young children to participate in fMRI investigations.

A twin study of cognitive costs of low birth weight and catch-up growth.

OBJECTIVE: To investigate whether there is an association between catch-up growth and cognitive performance in humans. STUDY DESIGN: Catch-up growth was defined as the change in weight standard deviation scores during the first 2 years of life. Cognitive performance was assessed with psychometric IQ tests, administered at ages 12 and 18 years. Data were collected in twin pairs, and analyses were carried out within pairs. RESULTS: There was a significant negative association between catch-up growth and IQ at both ages 12 and 18 years. CONCLUSIONS: A larger gain in weight during the first 2 years of life is associated with a lower IQ. However, catch-up growth is correlated with birth weight and this correlation may explain part of the association.

Glucocorticoid receptor gene variant is associated with increased body fatness in youngsters.

OBJECTIVE: Sensitivity to glucocorticoids is known to be highly variable between individuals and is partly determined by polymorphisms in the glucocorticoid receptor (GR) gene. We investigated the relationship between four GR gene polymorphisms and body composition during puberty and at young adult age. DESIGN: An observational study with repeated measurements. PATIENTS: Two comparable young Dutch cohorts with a generational difference of about 20 years were investigated. The first cohort consisted of 284 subjects born between 1961 and 1965. Measurements were performed from 13 to 36 years of age. The second cohort consisted of 235 subjects born between 1981 and 1989. Measurements were performed from 8 to 14 years of age. MEASUREMENTS: Associations between height, weight, BMI, fat mass (FM) and fat-free mass and four well-known functional polymorphisms were investigated. Results In boys in the younger cohort, the G-allele of the BclI polymorphism (haplotype 2) was associated with a higher body weight, weight-SDS, BMI, BMI-SDS and FM. These associations were not observed in the older cohort. Irrespective of genotype, the younger cohort showed a significantly higher total FM, body weight and BMI compared with the older cohort. CONCLUSIONS: Because the associations between the G-allele of the BclI polymorphism in the GR gene and body FM in boys were only found in a healthy young population, but not in a comparable, generally leaner cohort from an older generation, it is suggested that carriers of this polymorphism are likely to be more vulnerable to fat accumulation in today's obesity promoting environment, than noncarriers.

Growth during infancy and early childhood in relation to blood pressure and body fat measures at age 8-18 years of IVF children and spontaneously conceived controls born to subfertile parents.

BACKGROUND: Little is known about post-natal growth in IVF offspring and the effects of rates of early post-natal growth on blood pressure and body fat composition during childhood and adolescence. METHODS: The follow-up study comprised 233 IVF children aged 8-18 years and 233 spontaneously conceived controls born to subfertile parents. Growth data from birth to 4 years of age, available for 392 children (n = 193 IVF, n = 199 control), were used to study early post-natal growth. Furthermore, early post-natal growth velocity (weight gain) was related to blood pressure and skinfold measurements at follow-up. RESULTS: We found significantly lower weight, height and BMI standard deviation scores (SDSs) at 3 months, and weight SDS at 6 months of age in IVF children compared with controls. Likewise, IVF children demonstrated a greater gain in weight SDS (P < 0.001), height SDS (P = 0.013) and BMI SDS (P = 0.029) during late infancy (3 months to 1 year) versus controls. Weight gain during early childhood (1-3 years) was related to blood pressure in IVF children (P = 0.014 systolic, 0.04 diastolic) but not in controls. Growth during late infancy was not related to skinfold thickness in IVF children, unlike controls (P = 0.002 peripheral sum, 0.003 total sum). Growth during early childhood was related to skinfold thickness in both IVF and controls (P = 0.005 and 0.01 peripheral sum and P = 0.003 and 0.005 total sum, respectively). CONCLUSIONS: Late infancy growth velocity of IVF children was significantly higher compared with controls. Nevertheless, early childhood growth instead of infancy growth seemed to predict cardiovascular risk factors in IVF children. Further research is needed to confirm these findings and to follow-up growth and development of IVF children into adulthood.

Sex steroids and brain structure in pubertal boys and girls.

Sex steroids exert important organizational effects on brain structure. Early in life, they are involved in brain sexual differentiation. During puberty, sex steroid levels increase considerably. However, to which extent sex steroid production is involved in structural brain development during human puberty remains unknown. The relationship between pubertal rises in testosterone and estradiol levels and brain structure was assessed in 37 boys and 41 girls (10-15 years). Global brain volumes were measured using volumetric-MRI. Regional gray and white matter were quantified with voxel-based morphometry (VBM), a technique which measures relative concentrations ('density') of gray and white matter after individual global differences in size and shape of brains have been removed. Results showed that, corrected for age, global gray matter volume was negatively associated with estradiol levels in girls, and positively with testosterone levels in boys. Regionally, a higher estradiol level in girls was associated with decreases within prefrontal, parietal and middle temporal areas (corrected for age), and with increases in middle frontal-, inferior temporal- and middle occipital gyri. In boys, estradiol and testosterone levels were not related to regional brain structures, nor were testosterone levels in girls. Pubertal sex steroid levels could not explain regional sex differences in regional gray matter density. Boys were significantly younger than girls, which may explain part of the results. In conclusion, in girls, with the progression of puberty, gray matter development is at least in part directly associated with increased levels of estradiol, whereas in boys, who are in a less advanced pubertal stage, such steroid-related development could not (yet) be found. We suggest that in pubertal girls, estradiol may be implicated in neuronal changes in the cerebral cortex during this important period of brain development.

Glucocorticoid receptor gene polymorphism is less frequent in children born small for gestational age without catch-up growth.

BACKGROUND/AIMS: Glucocorticoids are important regulators of many processes involved in embryonal growth and development and fat and glucose metabolism. Glucocorticoids exert their effect through the glucocorticoid receptor (GR). The aim of this study was to investigate possible associations between 4 well-known GR gene haplotypes and size at birth. METHODS: We investigated associations between GR haplotypes and size at birth in a Dutch reference cohort. This reference cohort consisted of 222 young healthy Caucasian subjects. Associations between size at birth and glucocorticoid receptor gene haplotypes were tested. Furthermore, we investigated a group of 119 children born small for gestational age (SGA), without catch-up growth. Prevalence of the different GR haplotypes was compared between the SGA group and the reference cohort. RESULTS: No associations were found between any of the GR haplotypes and birth weight or birth length in the reference group. The prevalence of GR haplotype 2 (Bcl1) was significantly lower in the SGA group compared to controls. CONCLUSION: Genetic variance in the GR seems not to be associated with intrauterine growth in the general population. However, GR haplotype might play a role in growth of children born SGA, reflected by the decreased prevalence of GR haplotype 2 (Bcl1) in this group.

Heritability of testis size.

Testis size is an important feature of male pubertal development. The genetic and environmental contributions to variation in human testis size have hardly been studied. We estimated the heritability of human testicular size in a group of mono- and dizygotic twins and their non-twin brothers (145 twins and 20 brothers from 95 families). Participants were 18 years old on average and all had reached Tanner development stage 4 or higher. Dizygotic twins and their siblings had a larger mean testis volume than monozygotic twins and their siblings. There was significant familial resemblance, with higher correlations in monozygotic twin pairs (0.59) than in dizygotic twin and sibling pairs (0.34). Heritability was estimated at 59% (95% CI = 37-75%), but a model that excluded genetic influences and attributed all familial resemblance to shared environment, fitted the data only marginally worse. The finding of larger mean testis volume in dizygotic twins may be of interest for future research into the mechanisms underlying dizygotic twinning.