Fetal testosterone and sex differences in typical social development and in autism

Towards understanding sex differences in autism spectrum disorders

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by social deficits, repetitive behaviours and lack of empathy. Its significant genetic heritability and potential comorbidities often lead to diagnostic and therapeutic challenges. This review addresses the biological basis of ASD, focusing on the sex differences in gene expression and hormonal influences. ASD is more commonly diagnosed in males at a ratio of 4:1, indicating a potential oversight in female-specific ASD research and a risk of underdiagnosis in females. We consider how ASD manifests differently across sexes by exploring differential gene expression in female and male brains and consider how variations in steroid hormones influence ASD characteristics. Synaptic function, including excitation/inhibition ratio imbalance, is influenced by gene mutations and this is explored as a key factor in the cognitive and behavioural manifestations of ASD. We also discuss the role of micro RNAs (miRNAs) and highlight a novel mutation in miRNA-873, which affects a suite of key synaptic genes, neurexin, neuroligin, SHANK and post-synaptic density proteins, implicated in the pathology of ASD. Our review suggests that genetic predisposition, sex differences in brain gene expression, and hormonal factors significantly contribute to the presentation, identification and severity of ASD, necessitating sex-specific considerations in diagnosis and treatments. These findings advocate for personalized interventions to improve the outcomes for individuals with ASD.

Androgen levels in autism spectrum disorders: a systematic review and meta-analysis

Background

Accumulating evidence suggests that the autism spectrum disorder (ASD) population exhibits altered hormone levels, including androgens. However, studies on the regulation of androgens, such as testosterone and dehydroepiandrosterone (DHEA), in relation to sex differences in individuals with ASD are limited and inconsistent. We conducted the systematic review with meta-analysis to quantitatively summarise the blood, urine, or saliva androgen data between individuals with ASD and controls.

Methods

A systematic search was conducted for eligible studies published before 16 January 2023 in six international and two Chinese databases. We computed summary statistics with a random-effects model. Publication bias was assessed using funnel plots and heterogeneity using I2 statistics. Subgroup analysis was performed by age, sex, sample source, and measurement method to explain the heterogeneity.

Results

17 case-control studies (individuals with ASD, 825; controls, 669) were assessed. Androgen levels were significantly higher in individuals with ASD than that in controls (SMD: 0.27, 95% CI: 0.06-0.48, P=0.01). Subgroup analysis showed significantly elevated levels of urinary total testosterone, urinary DHEA, and free testosterone in individuals with ASD. DHEA level was also significantly elevated in males with ASD.

Conclusion

Androgen levels, especially free testosterone, may be elevated in individuals with ASD and DHEA levels may be specifically elevated in males.

TrkB-mediated neuroprotection in female hippocampal neurons is autonomous, estrogen receptor alpha-dependent, and eliminated by testosterone: a proposed model for sex differences in neonatal hippocampal neuronal injury

BACKGROUND

Neonatal hypoxia ischemia (HI) related brain injury is one of the major causes of learning disabilities and memory deficits in children. In both human and animal studies, female neonate brains are less susceptible to HI than male brains. Phosphorylation of the nerve growth factor receptor TrkB has been shown to provide sex-specific neuroprotection following in vivo HI in female mice in an estrogen receptor alpha (ERα)-dependent manner. However, the molecular and cellular mechanisms conferring sex-specific neonatal neuroprotection remain incompletely understood. Here, we test whether female neonatal hippocampal neurons express autonomous neuroprotective properties and assess the ability of testosterone (T) to alter this phenotype.

METHODS

We cultured sexed hippocampal neurons from ERα+/+ and ERα-/- mice and subjected them to 4 h oxygen glucose deprivation and 24 h reoxygenation (4-OGD/24-REOX). Sexed hippocampal neurons were treated either with vehicle control (VC) or the TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) following in vitro ischemia. End points at 24 h REOX were TrkB phosphorylation (p-TrkB) and neuronal survival assessed by immunohistochemistry. In addition, in vitro ischemia-mediated ERα gene expression in hippocampal neurons were investigated following testosterone (T) pre-treatment and TrkB antagonist therapy via q-RTPCR. Multifactorial analysis of variance was conducted to test for significant differences between experimental conditions.

RESULTS

Under normoxic conditions, administration of 3 µM 7,8-DHF resulted an ERα-dependent increase in p-TrkB immunoexpression that was higher in female, as compared to male neurons. Following 4-OGD/24-REOX, p-TrkB expression increased 20% in both male and female ERα+/+ neurons. However, with 3 µM 7,8-DHF treatment p-TrkB expression increased further in female neurons by 2.81 ± 0.79-fold and was ERα dependent. 4-OGD/24-REOX resulted in a 56% increase in cell death, but only female cells were rescued with 3 µM 7,8-DHF, again in an ERα dependent manner. Following 4-OGD/3-REOX, ERα mRNA increased ~ 3 fold in female neurons. This increase was blocked with either the TrkB antagonist ANA-12 or pre-treatment with T. Pre-treatment with T also blocked the 7,8-DHF- dependent sex-specific neuronal survival in female neurons following 4-OGD/24-REOX.

CONCLUSIONS

OGD/REOX results in sex-dependent TrkB phosphorylation in female neurons that increases further with 7,8-DHF treatment. TrkB phosphorylation by 7,8-DHF increased ERα mRNA expression and promoted cell survival preferentially in female hippocampal neurons. The sex-dependent neuroprotective actions of 7,8-DHF were blocked by either ANA-12 or by T pre-treatment. These results are consistent with a model for a female-specific neuroprotective pathway in hippocampal neurons in response to hypoxia. The pathway is activated by 7,8-DHF, mediated by TrkB phosphorylation, dependent on ERα and blocked by pre-exposure to T.

Excess neonatal testosterone causes male-specific social and fear memory deficits in wild-type mice

Neurodevelopmental disorders (ND) disproportionately affect males compared to females, and Autism Spectrum Disorder (ASD) in particular exhibits a 4:1 male bias. The biological mechanisms of this female protection or male susceptibility have not been identified. There is some evidence to suggest that fetal/neonatal gonadal hormones, which play pivotal roles in many aspects of development, may contribute. Here, we investigate the role of testosterone administration during a critical period of development, and its effects on social approach and fear learning in C57BL/6J wildtype mice. Male, but not female mice treated with testosterone on the day of birth (PN0) exhibited deficits in both social behavior and contextual fear conditioning, whereas mice treated with the same dose of testosterone on postnatal day 18 (PN18) did not display such impairments. Testosterone administration did not induce anxiogenic effects or lead to changes in body weight compared to the vehicle-treated group. These impairmeants are relevant to ND and may help identify novel treatment targets.

Sex Differences in Brain Disorders

A remarkable feature of the brain is its sexual dimorphism. Sexual dimorphism in brain structure and function is associated with clinical implications documented previously in healthy individuals but also in those who suffer from various brain disorders. Sex-based differences concerning some features such as the risk, prevalence, age of onset, and symptomatology have been confirmed in a range of neurological and neuropsychiatric diseases. The mechanisms responsible for the establishment of sex-based differences between men and women are not fully understood. The present paper provides up-to-date data on sex-related dissimilarities observed in brain disorders and highlights the most relevant features that differ between males and females. The topic is very important as the recognition of disparities between the sexes might allow for the identification of therapeutic targets and pharmacological approaches for intractable neurological and neuropsychiatric disorders.

Prevalence and risk factors of disabilities among Egyptian preschool children: a community-based population study

BACKGROUND

Child disability has significant implications on their well-being and healthcare systems.

AIM

This survey aimed to assess the magnitude of seven types of disability among Egyptian children aged 1 < 6 years and their socio-demographic, epidemiological, and perinatal predictors.

METHODS

A national population-based cross-sectional household survey targeting 21,316 children from eight governorates was conducted. The screening questionnaire was derived from the WHO ten-question survey tool validated for identifying seven disability categories.

RESULTS

The percentage of children with at least one disability was 8.1% as follows: speech/communication (4.4%), Mobility/physical (2.5%), Seizures (2.2%), Comprehension (1.7%), Intellectual impairment (1.4%), Visual (0.3%) and Hearing (0.2%). Age was not found to affect the odds of disability except for visual disability (significantly increased with age (AOR = 1.4, 95% CI:1.1-1.7). Male sex also increased the odds of all disabilities except visual, hearing, and seizures. Convulsions after birth significantly increased the odds of disability as follows: hearing (AOR = 8.1, 95% CI: 2.2-30.5), intellectual impairment (AOR = 4.2, 95% CI: 2.5-6.9), and mobility/physical (AOR = 3.4, 95% CI: 2.3-5.0). Preterm delivery and being kept in an incubator for more than two days after birth increased the odds for visual disability (AOR = 3.7, 95% CI: 1.1-12.1 & AOR = 3.7, 95% CI: 1.7-7.9 respectively). Cyanosis increased the odds of seizures (AOR = 4.7, 95% CI: 2.2-10.3). Low birth weight also increased the odds for all disability domains except for visual and hearing. Maternal health problems during pregnancy increased the odds for all types of disability except hearing and seizures. Higher paternal education decreased the odds for all disabilities by at least 30% except for vision and hearing.

CONCLUSION

The study found a high prevalence of disability among Egyptian children aged 1-6 years. It identified a number of modifiable risk factors for disability. The practice of early screening for disability is encouraged to provide early interventions when needed.

Prevalence and risk factors of disabilities among Egyptian preschool children: a community-based population study

Background

Child disability has significant implications on their well-being and healthcare systems. Aim: This survey aimed to assess the magnitude of seven types of disability among Egyptian children aged 1 < 6 years and their socio-demographic, epidemiological, and perinatal predictors.

Methods

A national population-based cross-sectional household survey targeting 21,316 children from eight governorates was conducted. The screening questionnaire was derived from the WHO ten-question survey tool validated for identifying seven disability categories.

Results

The percentage of children with at least one disability was 8.1% as follows: speech/communication (4.4%), Mobility/physical (2.5%), Seizures (2.2%), Comprehension (1.7%), Intellectual impairment (1.4%), Visual (0.3%) and Hearing (0.2%). Age was not found to affect the odds of disability except for visual disability (significantly increased with age (AOR = 1.4, 95% CI:1.1–1.7). Male sex also increased the odds of all disabilities except visual, hearing, and seizures. Convulsions after birth significantly increased the odds of disability as follows: hearing (AOR = 8.1, 95% CI: 2.2–30.5), intellectual impairment (AOR = 4.2, 95% CI: 2.5–6.9), and mobility/physical (AOR = 3.4, 95% CI: 2.3–5.0). Preterm delivery and being kept in an incubator for more than two days after birth increased the odds for visual disability (AOR = 3.7, 95% CI: 1.1–12.1 & AOR = 3.7, 95% CI: 1.7–7.9 respectively). Cyanosis increased the odds of seizures (AOR = 4.7, 95% CI: 2.2–10.3). Low birth weight also increased the odds for all disability domains except for visual and hearing. Maternal health problems during pregnancy increased the odds for all types of disability except hearing and seizures. Higher paternal education decreased the odds for all disabilities by at least 30% except for vision and hearing.

Conclusion

The study found a high prevalence of disability among Egyptian children aged 1–6 years. It identified a number of modifiable risk factors for disability. The practice of early screening for disability is encouraged to provide early interventions when needed.

Sex-dependent neuronal effects of α-synuclein reveal that GABAergic transmission is neuroprotective of sleep-controlling neurons

BACKGROUND

Sleep disorders (SDs) are a symptom of the prodromal phase of neurodegenerative disorders that are mechanistically linked to the protein α-synuclein (α-syn) including Parkinson's disease (PD). SDs during the prodromal phase could result from neurodegeneration induced in state-controlling neurons by accumulation of α-syn predominant early in the disease, and consistent with this, we reported the monomeric form of α-syn (monomeric α-syn; α-synM) caused cell death in the laterodorsal tegmental nucleus (LDT), which controls arousal as well as the sleep and wakefulness state. However, we only examined the male LDT, and since sex is considered a risk factor for the development of α-syn-related diseases including prodromal SDs, the possibility exists of sex-based differences in α-synM effects. Accordingly, we examined the hypothesis that α-synM exerts differential effects on membrane excitability, intracellular calcium, and cell viability in the LDT of females compared to males.

METHODS

Patch clamp electrophysiology, bulk load calcium imaging, and cell death histochemistry were used in LDT brain slices to monitor responses to α-synM and effects of GABA receptor acting agents.

RESULTS

Consistent with our hypothesis, we found differing effects of α-synM on female LDT neurons when compared to male. In females, α-synM induced a decrease in membrane excitability and heightened reductions in intracellular calcium, which were reliant on functional inhibitory acid transmission, as well as decreased the amplitude and frequency of spontaneous excitatory postsynaptic currents (sEPSCs) with a concurrent reduction in action potential firing rate. Cell viability studies showed higher α-synM-mediated neurodegeneration in males compared to females that depended on inhibitory amino acid transmission. Further, presence of GABA receptor agonists was associated with reduced cell death in males.

CONCLUSIONS

When taken together, we conclude that α-synM induces a sex-dependent effect on LDT neurons involving a GABA receptor-mediated mechanism that is neuroprotective. Understanding the potential sex differences in neurodegenerative processes, especially those occurring early in the disease, could enable implementation of sex-based strategies to identify prodromal PD cases, and promote efforts to illuminate new directions for tailored treatment and management of PD.

The metabolic role of vitamin D in children's neurodevelopment: a network study

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with various proposed environmental risk factors and a rapidly increasing prevalence. Mounting evidence suggests a potential role of vitamin D deficiency in ASD pathogenesis, though the causal mechanisms remain largely unknown. Here we investigate the impact of vitamin D on child neurodevelopment through an integrative network approach that combines metabolomic profiles, clinical traits, and neurodevelopmental data from a pediatric cohort. Our results show that vitamin D deficiency is associated with changes in the metabolic networks of tryptophan, linoleic, and fatty acid metabolism. These changes correlate with distinct ASD-related phenotypes, including delayed communication skills and respiratory dysfunctions. Additionally, our analysis suggests the kynurenine and serotonin sub-pathways may mediate the effect of vitamin D on early childhood communication development. Altogether, our findings provide metabolome-wide insights into the potential of vitamin D as a therapeutic option for ASD and other communication disorders.

Sex and age differences in social and cognitive function in offspring exposed to late gestational hypoxia

Background

Gestational sleep apnea affects 8-26% of pregnancies and can increase the risk for autism spectrum disorder (ASD) in offspring. ASD is a neurodevelopmental disorder associated with social dysfunction, repetitive behaviors, anxiety, and cognitive impairment. To examine the relationship between gestational sleep apnea and ASD-associated behaviors, we used a chronic intermittent hypoxia (CIH) protocol between gestational days (GD) 15-19 in pregnant rats to model late gestational sleep apnea. We hypothesized that late gestational CIH would produce sex- and age-specific social, mood, and cognitive impairments in offspring.

Methods

Timed pregnant Long-Evans rats were exposed to CIH or room air normoxia from GD 15-19. Behavioral testing of offspring occurred during either puberty or young adulthood. To examine ASD-associated phenotypes, we quantified ASD-associated behaviors (social function, repetitive behaviors, anxiety-like behaviors, and spatial memory and learning), hippocampal activity (glutamatergic NMDA receptors, dopamine transporter, monoamine oxidase-A, EGR-1, and doublecortin), and circulating hormones in offspring.

Results

Late gestational CIH induced sex- and age-specific differences in social, repetitive and memory functions in offspring. These effects were mostly transient and present during puberty. In female pubertal offspring, CIH impaired social function, increased repetitive behaviors, and increased circulating corticosterone levels, but did not impact memory. In contrast, CIH transiently induced spatial memory dysfunction in pubertal male offspring but did not impact social or repetitive functions. Long-term effects of gestational CIH were only observed in female offspring, wherein CIH induced social disengagement and suppression of circulating corticosterone levels in young adulthood. No effects of gestational CIH were observed on anxiety-like behaviors, hippocampal activity, circulating testosterone levels, or circulating estradiol levels, regardless of sex or age of offspring.

Conclusions

Our results indicate that hypoxia-associated pregnancy complications during late gestation can increase the risk for ASD-associated behavioral and physiological outcomes, such as pubertal social dysfunction, corticosterone dysregulation, and memory impairments.

The illusion of the mind-body divide is attenuated in males

A large literature suggests that people are intuitive Dualists-they tend to perceive the mind as ethereal, distinct from the body. Here, we ask whether Dualism emanates from within the human psyche, guided, in part, by theory of mind (ToM). Past research has shown that males are poorer mind-readers than females. If ToM begets Dualism, then males should exhibit weaker Dualism, and instead, lean towards Physicalism (i.e., they should view bodies and minds alike). Experiments 1-2 show that males indeed perceive the psyche as more embodied-as more likely to emerge in a replica of one's body, and less likely to persist in its absence (after life). Experiment 3 further shows that males are less inclined towards Empiricism-a putative byproduct of Dualism. A final analysis confirms that males' ToM scores are lower, and ToM scores further correlate with embodiment intuitions (in Experiments 1-2). These observations (from Western participants) cannot establish universality, but the association of Dualism with ToM suggests its roots are psychological. Thus, the illusory mind-body divide may arise from the very workings of the human mind.

Sex differences matter: Males and females are equal but not the same

Sex differences between males and females can be detected early in life. They are present also later even to a much greater extent affecting our life in adulthood and a wide spectrum of physical, psychological, cognitive, and behavioral characteristics. Moreover, sex differences matter also in individual's health and disease. In this article, we reviewed at first the sex differences in brain organization and function with respect to the underlying biological mechanisms. Since the individual functional differences in the brain, in turn, shape the behavior, sex-specific psychological/behavioral differences that can be observed in infants but also adults are consequently addressed. Finally, we briefly mention sex-dependent variations in susceptibility to selected disorders as well as their pathophysiology, diagnosis, and response to therapy. The understanding of biologically determined variability between males and females can have important implications, especially in gender-specific health care. We have the impression that it is very important to emphasize that sex matters. Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.

Thyroid hormone elicits intergenerational epigenetic effects on adult social behavior and fetal brain expression of autism susceptibility genes

Genetic mutations identified in genome-wide association studies can only explain a small percentage of the cases of complex, highly heritable human conditions, including neurological and neurodevelopmental disorders. This suggests that intergenerational epigenetic effects, possibly triggered by environmental circumstances, may contribute to their etiology. We previously described altered DNA methylation signatures in the sperm of mice that experienced developmental overexposure to thyroid hormones as a result of a genetic defect in hormone clearance (DIO3 deficiency). Here we studied fetal brain gene expression and adult social behavior in genetically normal F2 generation descendants of overexposed mice. The brain of F2 generation E13.5 fetuses exhibited abnormal expression of genes associated with autism in humans, including Auts2, Disc1, Ldlr, Per2, Shank3, Oxtr, Igf1, Foxg1, Cd38, Grid2, Nrxn3, and Reln. These abnormal gene expression profiles differed depending on the sex of the exposed ancestor. In the three-chamber social box test, adult F2 generation males manifested significantly decreased interest in social interaction and social novelty, as revealed by decrease total time, distance traveled and time immobile in the area of interaction with novel strangers. F1 generation mice, compared to appropriate controls also exhibited altered profiles in fetal brain gene expression, although these profiles were substantially different to those in the F2 generation. Likewise adult F1 generation mice showed some abnormalities in social behavior that were sexually dimorphic and milder than those in F2 generation mice. Our results indicate that developmental overexposure to thyroid hormone causes intergenerational epigenetic effects impacting social behavior and the expression of autism-related genes during early brain development. Our results open the possibility that altered thyroid hormone states, by eliciting changes in the epigenetic information of the germ line, contribute to the susceptibility and the missing-but heriTables-etiology of complex neurodevelopmental conditions characterized by social deficits, including autism and schizophrenia.

Drug repurposing candidates to treat core symptoms in autism spectrum disorder

Autism spectrum disorder (ASD) is characterized by high heritability and clinical heterogeneity. The main core symptoms are social communication deficits. There are no medications approved for the treatment of these symptoms, and medications used to treat non-specific symptoms have serious side effects. To identify potential drugs for repurposing to effectively treat ASD core symptoms, we studied ASD risk genes within networks of protein-protein interactions of gene products. We first defined an ASD network from network-based analyses, and identified approved drugs known to interact with proteins within this network. Thereafter, we evaluated if these drugs can change ASD-associated gene expression perturbations in genes in the ASD network. This was done by analyses of drug-induced versus ASD-associated gene expression, where opposite gene expression perturbations in drug versus ASD indicate that the drug could counteract ASD-associated perturbations. Four drugs showing significant (p < 0.05) opposite gene expression perturbations in drug versus ASD were identified: Loperamide, bromocriptine, drospirenone, and progesterone. These drugs act on ASD-related biological systems, indicating that these drugs could effectively treat ASD core symptoms. Based on our bioinformatics analyses of ASD genetics, we shortlist potential drug repurposing candidates that warrant clinical translation to treat core symptoms in ASD.

Elevated prenatal maternal sex hormones, but not placental aromatase, are associated with child neurodevelopment

Fetal exposure to testosterone may contribute to vulnerability for autism spectrum disorder (ASD). It is hypothesized that placental aromatase prevents fetal exposure to maternal testosterone, however, this pathway and the implications for child neurodevelopment have not been fully explored. We examined the relationships between prenatal maternal testosterone and estradiol at 19.2 ± 1.3 weeks, cord blood testosterone and estradiol at birth, placental aromatase mRNA expression, and neurodevelopment using the Social Communication Questionnaire (SCQ), the Behavioral Assessment System for Children, 3rd Edition (BASC-3), and the Empathizing Quotient for Children (EQ-C) at 4.5-6.5 years of age in a sample of 270 Nulliparous-Mothers-to-be (nuMoM2b) study participants. Maternal testosterone levels were positively associated with SCQ scores, but the association was not significant after adjusting for maternal age at delivery, nor was there a significant interaction with sex. Maternal estradiol levels were negatively associated with BASC-3 Clinical Probability scores among males (n = 139). We report a significant interaction effect of cord blood testosterone and fetal sex on both total SCQ scores and t-scores on the Developmental Social Disorders subscale. Placental aromatase was not associated with any neurodevelopmental or hormone measure, but under conditions of low placental aromatase expression, high maternal testosterone was positively associated with SCQ scores in males (n = 46). No other associations between hormone levels and neurodevelopment were significant. Our findings provide a foundation for further investigation of the mechanisms through which maternal sex hormones and placental steroidogenesis may affect fetal hormone production and neurobehavior.

Maternal polycystic ovary syndrome and the potential risk of attention-deficit/hyperactivity disorder and autism spectrum disorder in the offspring: a systematic review and meta-analysis

OBJECTIVE

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are two increasing important problems among children. This study aims to explore the link between maternal polycystic ovary syndrome (PCOS) and the risk of ASD and ADHD in the offspring.

METHOD

The MOOSE guidelines were followed in the conduct of this meta-analysis. A literature search was done in PubMed/MEDLINE, Scopus, and Web of Science from inception until January 2021. The DerSimonian and Laird random-effects model was used to estimate the combined risk ratios (RR) and 95% confidence intervals (CI). Sensitivity analysis was also used to investigate the effect of each study on the combined results.

RESULTS

Seven studies, with 1,358,696 participants, comprising 7,334 ADHD cases and 3,920 ASD cases, were included in this study. Children born to mothers with maternal PCOS had higher risks of developing ASD (RR = 1.46, 95% CI: 1.26-1.69, I² = 64%) and ADHD (RR = 1.43, 95% CI: 1.35-1.41, I² = 0%) when compared with children born to mothers without maternal PCOS.

CONCLUSION

This study showed that there might be a link between maternal PCOS and the risk of developing ASD and ADHD in the offspring. This important issue must be considered in PCOS women during and after pregnancy.

Hypertensive disorders during pregnancy and polycystic ovary syndrome are associated with child communication and social skills in a sex-specific and androgen-dependent manner

Prenatal exposure to testosterone is implicated in the etiology of autism spectrum disorder (ASD). Hypertensive disorders of pregnancy and polycystic ovary syndrome are associated with both hyperandrogenism and increased risk for ASD. We examined whether increased maternal testosterone mediates the relationship between these hyperandrogenic disorders (HDs) during pregnancy and child communication and social skills. Maternal plasma was collected during the second trimester and parent-report measures of child communication and social skills were obtained at 4.5-6.5 years of age from 270 participants enrolled in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b). Our retrospective frequency-matched cohort study design identified 58 mothers with one or both of the HDs and 58 matched controls. Women diagnosed with an HD who carried a female had higher testosterone levels compared to those carrying a male (t(56) = -2.70, p = 0.01). Compared to females controls, females born to women with an HD had significantly higher scores on the Social Communication Questionnaire (t(114) = -2.82, p =0.01). Maternal testosterone partially mediated the relationship between a diagnosis of an HD and SCQ scores among females. These findings point to sex-specific associations of two HDs - hypertensive disorders of pregnancy and polycystic ovary syndrome - on child communication and social skills and a mediating effect of maternal testosterone during pregnancy. Further research is needed to understand placental-mediated effects of maternal testosterone on child brain development and neurodevelopmental outcomes.

Short-term and long-term mate preference in men and women in an Iranian population

Mate preference in short-term relationships and long-term ones may depend on many physical, psychological, and socio-cultural factors. In this study, 178 students (81 females) in sports and 153 engineering students (64 females) answered the systemizing quotient (SQ) and empathizing quotient (EQ) questionnaires and had their digit ratio measured. They rated their preferred mate on 12 black-line drawing body figures varying in body mass index (BMI) and waist to hip ratio (WHR) for short-term and long-term relationships. Men relative to women preferred lower WHR and BMI for mate selection for both short-term and long-term relationships. BMI and WHR preference in men is independent of each other, but has a negative correlation in women. For men, digit ratio was inversely associated with BMI (p = 0.039, B = − 0.154) preference in a short-term relationship, and EQ was inversely associated with WHR preference in a long-term relationship (p = 0.045, B = − 0.164). Furthermore, men and women in sports, compared to engineering students, preferred higher (p = 0.009, B = 0.201) and lower BMI (p = 0.034, B = − 0.182) for short-term relationships, respectively. Women were more consistent in their preferences for short-term and long-term relationships relative to men. Both biological factors and social/experiential factors contribute to mate preferences in men while in women, mostly social/experiential factors contribute to them.

Klinefelter syndrome in an adolescent with severe obesity, insulin resistance, and hyperlipidemia, successfully treated with testosterone replacement therapy

Klinefelter syndrome (KS) is a sex chromosome disorder characterized by the presence of one or more extra X chromosomes. KS is well known by the common karyotype 47, XXY and presents as male infertility with hypogonadism in adults. Pediatric patients with KS commonly show neurodevelopmental disorders and cryptorchidism. We have reported a case of a 14-yr-old boy with KS and severe obesity (body mass index, 38.1 kg/m²), insulin (IRI) resistance (homeostatic model assessment 1 IRI resistance, 9.26), hyperlipidemia (serum low-density lipoprotein cholesterol level, 192 mg/dL; serum triglyceride level, 239 mg/dL), hypergonadotropic hypogonadism, and learning difficulties. The karyotype was 47, XXY, t(4;5) (q21.2;q32). Initially, he was unwilling to accept dietary restrictions and perform physical exercise against obesity. Testosterone replacement therapy was initiated at 16 years of age, which successfully improved the body composition, IRI resistance, and hyperlipidemia and increased the serum testosterone levels. Additionally, he adhered to recommendations for exercise and dietary restrictions. Patients with KS have risks of obesity and metabolic syndrome with sarcopenic conditions due to hypergonadotropic hypogonadism. Pediatricians should be aware of KS as a primary disease causing obesity. Testosterone replacement therapy could help ameliorate obesity and its comorbidities in patients with obesity and KS.

Genetic and morphological estimates of androgen exposure predict social deficits in multiple neurodevelopmental disorder cohorts

BACKGROUND

Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD) display a strong male bias. Androgen exposure is profoundly increased in typical male development, but it also varies within the sexes, and previous work has sought to connect morphological proxies of androgen exposure, including digit ratio and facial morphology, to neurodevelopmental outcomes. The results of these studies have been mixed, and the relationships between androgen exposure and behavior remain unclear.

METHODS

Here, we measured both digit ratio masculinity (DRM) and facial landmark masculinity (FLM) in the same neurodevelopmental cohort (N = 763) and compared these proxies of androgen exposure to clinical and parent-reported features as well as polygenic risk scores.

RESULTS

We found that FLM was significantly associated with NDD diagnosis (ASD, ADHD, ID; all [Formula: see text]), while DRM was not. When testing for association with parent-reported problems, we found that both FLM and DRM were positively associated with concerns about social behavior ([Formula: see text], [Formula: see text]; [Formula: see text], [Formula: see text], respectively). Furthermore, we found evidence via polygenic risk scores (PRS) that DRM indexes masculinity via testosterone levels ([Formula: see text], [Formula: see text]), while FLM indexes masculinity through a negative relationship with sex hormone binding globulin (SHBG) levels ([Formula: see text], [Formula: see text]). Finally, using the SPARK cohort (N = 9419) we replicated the observed relationship between polygenic estimates of testosterone, SHBG, and social functioning ([Formula: see text], [Formula: see text], and [Formula: see text], [Formula: see text] for testosterone and SHBG, respectively). Remarkably, when considered over the extremes of each variable, these quantitative sex effects on social functioning were comparable to the effect of binary sex itself (binary male: [Formula: see text]; testosterone: [Formula: see text] from 0.1%-ile to 99.9%-ile; SHBG: [Formula: see text] from 0.1%-ile to 99.9%-ile).

LIMITATIONS

In the devGenes and SPARK cohorts, our analyses rely on indirect, rather than direct measurement of androgens and related molecules.

CONCLUSIONS

These findings and their replication in the large SPARK cohort lend support to the hypothesis that increasing net androgen exposure diminishes capacity for social functioning in both males and females.

Sexuality and Gender Issues in Individuals with Autism Spectrum Disorder

This article reviews relevant literature on sexuality in individuals with autism spectrum disorder (ASD). Findings reveal a growing awareness of desire for sexual and intimate relationships in individuals with ASD. However, core impairments of ASD lead to difficulties establishing requisite knowledge and skills necessary to attain a healthy sexuality and facilitate relationships. Consequently, individuals with ASD present with increased risk of engaging in inappropriate sexual behaviors and sexual victimization than their typically developing peers. The literature asserts the need to implement effective sexual education programs to assist in development of healthy sexual identity and relationships that meet each individual's needs.

No evidence for a difference in 2D:4D ratio between youth with elevated prenatal androgen exposure due to congenital adrenal hyperplasia and controls

The second-to-fourth digit ratio (2D:4D) has been associated with sexual dimorphism, with a lower 2D:4D in males. A large body of research has relied on the 2D:4D as a proxy for prenatal androgen exposure, and includes reports of relationships between 2D:4D and a wide range of human traits. Here, we examine the validity of the 2D:4D proxy by studying the association between 2D:4D and classical Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency, a condition characterized by excessive prenatal exposure to androgens during most of the gestational period. To this end, we retrospectively examine 513 serial radiographs of the left hand obtained clinically in 90 youth with classical CAH (45 female) and 70 control youth (31 female). Replicating previous reports, we observe associations of the 2D:4D with sex (lower 2D:4D in males) and age (increase of 2D:4D through development). However, we find no evidence for differences in 2D:4D between CAH and controls (full sample: β = -0.001 (-0.008, 0.006); females: β = -0.004 [-0.015, 0.007]; males: β = 0.001, [-0.008, 0.011]). Although our findings do not rule out a small association between the 2D:4D and CAH, they cast doubt on the usefulness of the 2D:4D as a biomarker for prenatal androgen exposure in behavioral research.

Testosterone and the Brain: From Cognition to Autism

Sex and gender matter in all aspects of life. Humans exhibit sexual dimorphism in anatomy, physiology, but also pathology. Many of the differences are due to sex chromosomes and, thus, genetics, other due to endocrine factors such as sex hormones, some are of social origin. Over the past decades, huge number of scientific studies have revealed striking sex differences of the human brain with remarkable behavioral and cognitive consequences. Prenatal and postnatal testosterone influence brain structures and functions, respectively. Cognitive sex differences include especially certain spatial and language tasks, but they also affect many other aspects of the neurotypical brain. Sex differences of the brain are also relevant for the pathogenesis of neuropsychiatric disorders such as autism spectrum disorders, which are much more prevalent in the male population. Structural dimorphism in the human brain was well-described, but recent controversies now question its importance. On the other hand, solid evidence exists regarding gender differences in several brain functions. This review tries to summarize the current understanding of the complexity of the effects of testosterone on brain with special focus on their role in the known sex differences in healthy individuals and people in the autism spectrum.

A Unifying Theory for Autism: The Pathogenetic Triad as a Theoretical Framework

This paper presents a unifying theory for autism by applying the framework of a pathogenetic triad to the scientific literature. It proposes a deconstruction of autism into three contributing features (an autistic personality dimension, cognitive compensation, and neuropathological risk factors), and delineates how they interact to cause a maladaptive behavioral phenotype that may require a clinical diagnosis. The autistic personality represents a common core condition, which induces a set of behavioral issues when pronounced. These issues are compensated for by cognitive mechanisms, allowing the individual to remain adaptive and functional. Risk factors, both exogenous and endogenous ones, show pathophysiological convergence through their negative effects on neurodevelopment. This secondarily affects cognitive compensation, which disinhibits a maladaptive behavioral phenotype. The triad is operationalized and methods for quantification are presented. With respect to the breadth of findings in the literature that it can incorporate, it is the most comprehensive model yet for autism. Its main implications are that (1) it presents the broader autism phenotype as a non-pathological core personality domain, which is shared across the population and uncoupled from associated features such as low cognitive ability and immune dysfunction, (2) it proposes that common genetic variants underly the personality domain, and that rare variants act as risk factors through negative effects on neurodevelopment, (3) it outlines a common pathophysiological mechanism, through inhibition of neurodevelopment and cognitive dysfunction, by which a wide range of endogenous and exogenous risk factors lead to autism, and (4) it suggests that contributing risk factors, and findings of immune and autonomic dysfunction are clinically ascertained rather than part of the core autism construct.

Meconium androgens are correlated with ASD-related phenotypic traits in early childhood in a familial enriched risk cohort

BACKGROUND

Prenatal exposure to increased androgens has been suggested as a risk factor for autism spectrum disorder (ASD). This hypothesis has been examined by measurement of steroids in amniotic fluid, cord blood, saliva, and blood with mixed results.

METHODS

To provide an orthogonal measure of fetal exposure, this study used meconium, the first stool of a newborn, to measure prenatal androgen exposure from infants in the Early Autism Risk Longitudinal Investigation (EARLI). EARLI is a familial-enriched risk cohort that enrolled pregnant mothers who already had a child with an ASD diagnosis. In the younger child, we investigated the association between meconium unconjugated (u) and total (t) concentrations of major androgens testosterone (T), dehydroepiandrosterone (DHEA), and androstenedione (A4), and ASD-related traits at 12 and 36 months of age. Traits were measured at 12 months with Autism Observation Scale for Infants (AOSI) and at 36 months with total score on the Social Responsiveness Scale (SRS). One hundred and seventy children had meconium and AOSI, 140 had meconium and SRS, and 137 had meconium and both AOSI and SRS.

RESULTS

Separate robust linear regressions between each of the log-transformed androgens and log-transformed SRS scores revealed three-way interaction between sex of the child, sex of the proband, and testosterone concentration. In the adjusted analyses, t-T, u-A4, and u-DHEA (P ≤ 0.01) were positively associated with AOSI scores, while u-T (P = 0.004) and u-DHEA (P = 0.007) were positively associated with SRS total score among females with female probands (n = 10). Additionally, higher concentrations of u-T (P = 0.01) and t-T (P = 0.01) predicted higher SRS total score in males with male probands (n = 63). Limitations Since we explored three-way interactions, this resulted in a limited sample size for some analyses. This study was from an enriched-risk cohort which may limit generalizability, and this study used ASD-assessment scales as outcomes instead of diagnostic categories. Additionally, the novel use of meconium in this study limits the ability to compare the results in this cohort to others due to the paucity of research on meconium.

CONCLUSIONS

This study supports the utility of meconium for studies of endogenous fetal metabolism and suggests the sex of older siblings with autism should be considered as a biological variable in relevant studies.

Social Cognition in Autism Spectrum Disorder Across the Adult Lifespan: Influence of Age and Sex on Reading the Mind in the Eyes Task in a Cross-sectional Sample

Background: Approximately 50,000 U.S. teens with autism spectrum disorder (ASD) become adults every year, however little is known regarding how age influences social cognition and if men and women with ASD are differentially impacted across the adult lifespan. Social cognition declines non-linearly with age in neurotypical (NT) adults. Moreover, sex differences have been observed on RME tasks in NT adults but not adults with ASD, although aging effects have been largely ignored.

Objective: This cross-sectional study examined the influence of age and sex on social cognition in adults with ASD compared to NT adults.

Methods: The Reading the Mind in the Eyes (RME) task was administered to evaluate the theory of mind abilities in 95 adults with ASD and 82 NT adults ages 18–71 years. The main effects of diagnosis, age, and sex, as well as two-way and three-way interaction were modeled using linear and quadratic aging terms in a multiple regression analysis.

Results: A main effect of diagnosis was observed, indicating poorer performance in adults with ASD relative to NT adults. Age and sex interactions were nonsignificant.

Discussion: We replicated previous findings of reduced theory of mind (ToM) abilities in adults with ASD, compared to NT adults. While interactions were nonsignificant, visual inspection of quadratic age curves indicated the possibility of unique ToM trajectories in men and women with and without ASD that should be investigated in larger longitudinal studies.

Gender identity, sexual orientation and adverse sexual experiences in autistic females

BACKGROUND

There is growing recognition that autistic females present with more diverse gender and sexual identities than their non-autistic counterparts. Likewise, autistic females are also at an increased risk of adverse sexual experiences. As higher rates of sexual victimisation are observed in individuals with diverse sexual identities in the broader population, rates of negative sexual experiences among autistic females remain unclear. This study aimed to investigate the representation of gender and sexual diversity within autistic females and examine their rates of regretted, and unwanted, sexual encounters among females with a transgender gender identity and non-heterosexual sexual orientation.

METHODS

Two hundred and ninety-five females completed the Sexual Behaviour Scale-III (SBS-III) online. Self-reported gender identity and sexual orientation were compared between 134 autistic (M_age= 26.2 years, SD = 8.7) and 161 non-autistic females (M_age = 22.0 years, SD = 4.6). Differences in the prevalence of negative sexual experiences were compared across diagnosis and each gender identity and sexual orientation label.

RESULTS

Autistic females were more likely to identify with a transgender gender identity (p < .05) and non-heterosexual sexual orientation (p < .007) compared to non-autistic females. Autistic homosexual females were more likely to have experienced a range of negative sexual experiences than autistic heterosexual females (OR ≥ 3.29; p < .01) and were more likely to have experienced unwanted sexual experiences than non-autistic females regardless of sexual orientation (OR ≥ 2.38; p < .05). There were no differences in rates of negative sexual experiences between autistic bisexual and both autistic heterosexual and non-autistic bisexual females. Non-autistic bisexual females (OR = 0.24; p = .018) presented with a reduced risk of regretted sexual experiences than non-autistic heterosexual peers. There were no differences in negative sexual experiences across gender identity in the autistic sample.

LIMITATIONS

The use of fixed format response items may have restricted participants' abilities to provide rich responses pertaining to their sexual identities and nature of negative sexual experiences. The small number of participants who identified as transgender (n = 40) limits the reliability of results pertaining to sexual experiences across gender identity. Moreover, although multiple recruitment methods were used in this study, non-representative may bias estimates of prevalence rates. Thus, the data may not be representative of the broader population.

CONCLUSIONS

Results indicate that autistic females present with greater diversity in their sexual identities than individuals without autism, with those with a homosexual sexual orientation being at greater risk of experiencing adverse sexual encounters. Findings suggest the importance of increased clinical attention to this diversity and the need to provide support to facilitate the development of a healthy sexual identity and reduce the risks identified in this study.

Sexuality and Gender Issues in Individuals with Autism Spectrum Disorder

This article reviews relevant literature on sexuality in individuals with autism spectrum disorder (ASD). Findings reveal a growing awareness of desire for sexual and intimate relationships in individuals with ASD. However, core impairments of ASD lead to difficulties establishing requisite knowledge and skills necessary to attain a healthy sexuality and facilitate relationships. Consequently, individuals with ASD present with increased risk of engaging in inappropriate sexual behaviors and sexual victimization than their typically developing peers. The literature asserts the need to implement effective sexual education programs to assist in development of healthy sexual identity and relationships that meet each individual's needs.

Lower digit ratio and higher endogenous testosterone are associated with lower empathic accuracy

Empathy is a cornerstone of human sociality. It has important consequences for our interpersonal relationships and for navigating our social world more generally. Although research has identified numerous psychological factors that can influence empathy, evidence suggests that empathy may also be rooted in our biology and, in particular, the gonadal steroid hormone testosterone. To date, much of the research linking testosterone and empathy has focused on the 2D:4D ratio (i.e., the ratio of the lengths of the index and ring fingers), and the results have been mixed. These mixed results, however, may be due to reliance on self-report measures to assess empathy, which can be vulnerable to self-presentation, as well as social-cultural norms about gender/sex differences in empathy. Moreover, although some have argued that digit ratio is an indicator of prenatal androgen exposure, the evidence for this to date is weak. Here, we aimed to follow up on this prior work, using a naturalistic empathic accuracy task in which participants dynamically track, in real-time, the emotional state of targets. We show that lower digit ratio (Study 1; N = 107) and higher circulating testosterone (Study 2; N = 76) are associated with poorer empathic accuracy performance; critically, these effects hold when controlling for sex/gender. In neither study, however, did we find effects on self-reported empathy. Our results highlight the limitations of self-report measures and support the notion that endogenous testosterone levels as well as 2D:4D ratio are related to key social-cognitive competencies like empathic accuracy.

Anogenital distance as a measure of male competitive ability in Rwenzori Angolan colobus

Anogenital distance (AGD) is positively correlated to fetal androgen exposure and developmental masculinization in mammals. Independent of overall body size, AGD shows a strong positive correlation with male fertility and in rodents, AGD is a good indicator of male competitive ability and is associated with female choice. We hypothesized that AGD will also predict male competitive ability in non-human primates. To test this, we measured AGD noninvasively with a parallel laser in a wild population of Angolan colobus monkeys (Colobus angolensis ruwenzorii) in Uganda and correlated to it to their social structure. C. angolensis ruwenzorii form a multilevel society with both one-male/multifemale units (OMUs) and multimale/multifemale units (MMUs). We compared AGD in males from five OMUs and six MMUs and related it to their fecal androgen metabolite concentrations, dominance rank and body size, and to the number of females in their unit. Males in OMUs had greater access to females, so were predicted to have longer AGDs, but this was not found. AGD also did not correlate overall with mean fecal androgen metabolites in MMUs. However, AGD was correlated with dominance rank in MMUs, demonstrating that higher-ranking males in these multimale units had longer AGDs. Body size did not show the same relationship with dominance rank, suggesting that male rank was not just a reflection of absolute male size. Our findings indicate that AGD predicts male competitive ability in this species and that it may be a useful correlate throughout the non-human primates. These results also support the idea that prenatal androgen exposure increases the likelihood of the expression of behaviors that maintain high dominance rank.

Bayesian regression-based developmental norms for the Benton Facial Recognition Test in males and females

Face identity recognition is important for social interaction and is impaired in a range of clinical disorders, including several neurodevelopmental disorders. The Benton Facial Recognition Test (BFRT; Benton & Van Allen, 1968), a widely used assessment of identity recognition, is the only standardized test of face identity perception, as opposed to face memory, that has been normed on children and adolescents. However, the existing norms for the BFRT are suboptimal, with several ages not represented and no established time limit (which can lead to inflated scores by allowing individuals with prosopagnosia to use feature matching). Here we address these issues with a large normative dataset of children and adolescents (ages 5-17, N = 398) and adults (ages 18-55; N = 120) who completed a time-limited version of the BFRT. Using Bayesian regression, we demonstrate that face identity perception increases asymptotically from childhood through adulthood, and provide continuous norms based on age and sex that can be used to calculate standard scores. We show that our time limit of 16 seconds per item yields scores comparable to the existing norms without time limits from the non-prosopagnostic samples. We also find that females (N = 156) score significantly higher than males (N = 362), supporting the existence of a female superiority effect for face identification. Overall, these results provide more robust norms for the BFRT and promote future research on face identity perception in developmental populations.

Maternal polycystic ovarian syndrome in autism spectrum disorder: a systematic review and meta-analysis

There is evidence showing a positive correlation between prenatal androgens and their effect on the development of central nervous system and the autistic spectrum disorder (ASD) phenotype in offspring of mothers with polycystic ovary syndrome (PCOS). We applied a systematic review to investigate whether women with PCOS have increased odds of having a child with ASD, while, secondarily, if these women themselves are at high risk of having the disease. Major databases from inception until 14th October 2018 were searched. The primary outcome measure was the odds of an ASD diagnosis in children of mothers with diagnosed PCOS, while the secondary outcome was the odds of ASD diagnosis in women with PCOS. Scheduled subgroup analyses were according to the time of birth and maternal age. We assessed the odds ratio (OR), using a random-effects model; heterogeneity was assessed by I² and τ² statistics. The quality of the evidence was evaluated using the Newcastle-Ottawa Scale. Ten studies were eligible for inclusion, including a total of 33,887 ASD children and 321,661 non-ASD children. Diagnosed PCOS was associated with a 1.66 times increase in the odds of ASD in the offspring [95% CI: 1.51, 1.83, p = 1.99 × 10^-25, 7 studies, I² = 0%, τ² = 0]. Women with PCOS were 1.78 times more likely to be diagnosed with ASD (95% CI: 1.10, 2.87, p = 0.0179, 5 studies, I² = 85.4%, τ² = 0.2432). Additional analyses did not change the initial result. The overall quality of the evidence was high. The pooled effects size displayed low heterogeneity (I² = 0%) for the primary outcome. While the heterogeneity in the secondary outcome appears to attenuate when only high quality studies are synthesized, still the result exhibits significant heterogeneity. Τhe available data allowed a subgroup analysis only for classification system for PCOS diagnosis and showed a significant increase of ASD diagnosis in the offspring of women with Read Code and ICD diagnosed PCOS. In conclusion, the available evidence suggests that women with PCOS have increased odds of having a child with ASD, an effect size estimate based on a large number of patients from studies of good quality. Regarding the evidence on the prevalence of ASD in PCOS women, results suggest that women with PCOS are more likely to be diagnosed with ASD.

Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys

Perhaps due to different roles they have had in social groups during evolution, men and women differ in their verbal abilities. These differences are also (if not even more) present in children, both in the course of typical and pathological development. Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. The sex-related difference in the prevalence of these disorders is especially pronounced in autism spectrum disorder (1 girl for each 4-5 boys is affected). The aim of this review is to present the sex differences in typical communication and language development and in the prevalence of communication-related neurodevelopmental disorders. Also, a special focus is put on data from the field of neuroscience that might provide insight into the neurobiological mechanisms that can add to the understanding of this phenomenon. We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

What About the Girls? Sex-Based Differences in Autistic Traits and Adaptive Skills

There is growing evidence of a camouflaging effect among females with autism spectrum disorder (ASD), particularly among those without intellectual disability, which may affect performance on gold-standard diagnostic measures. This study utilized an age- and IQ-matched sample of school-aged youth (n = 228) diagnosed with ASD to assess sex differences on the ADOS and ADI-R, parent-reported autistic traits, and adaptive skills. Although females and males were rated similarly on gold-standard diagnostic measures overall, females with higher IQs were less likely to meet criteria on the ADI-R. Females were also found to be significantly more impaired on parent reported autistic traits and adaptive skills. Overall, the findings suggest that some autistic females may be missed by current diagnostic procedures.

Crmp4-KO Mice as an Animal Model for Investigating Certain Phenotypes of Autism Spectrum Disorders

Previous research has demonstrated that the collapsin response mediator protein (CRMP) family is involved in the formation of neural networks. A recent whole-exome sequencing study identified a de novo variant (S541Y) of collapsin response mediator protein 4 (CRMP4) in a male patient with autism spectrum disorder (ASD). In addition, Crmp4-knockout (KO) mice show some phenotypes similar to those observed in human patients with ASD. For example, compared with wild-type mice, Crmp4-KO mice exhibit impaired social interaction, abnormal sensory sensitivities, broader distribution of activated (c-Fos expressing) neurons, altered dendritic formation, and aberrant patterns of neural gene expressions, most of which have sex differences. This review summarizes current knowledge regarding the role of CRMP4 during brain development and discusses the possible contribution of CRMP4 deficiencies or abnormalities to the pathogenesis of ASD. Crmp4-KO mice represent an appropriate animal model for investigating the mechanisms underlying some ASD phenotypes, such as impaired social behavior, abnormal sensory sensitivities, and sex-based differences, and other neurodevelopmental disorders associated with sensory processing disorders.

Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys

Perhaps due to different roles they have had in social groups during evolution, men and women differ in their verbal abilities. These differences are also (if not even more) present in children, both in the course of typical and pathological development. Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. The sex-related difference in the prevalence of these disorders is especially pronounced in autism spectrum disorder (1 girl for each 4-5 boys is affected). The aim of this review is to present the sex differences in typical communication and language development and in the prevalence of communication-related neurodevelopmental disorders. Also, a special focus is put on data from the field of neuroscience that might provide insight into the neurobiological mechanisms that can add to the understanding of this phenomenon. We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

Prenatal Risk for ASD: Fetal Cortisol Exposure Predicts Child Autism-Spectrum Disorder Symptoms

The etiology of autism spectrum disorder (ASD) is multifactorial and complex and likely involves interactions among genetic, epigenetic and environmental factors. With respect to environmental influences, a growing literature implicates intrauterine experiences in the origin of this pervasive developmental disorder. In this prospective longitudinal design, we examine the hypothesis that fetal exposure to maternal cortisol may confer ASD risk. In addition, because ASD is four times more prevalent in males than females and because sexually dimorphic responses to intrauterine experiences are commonly observed, we examine whether or not any associations differ by fetal sex. Maternal plasma cortisol was measured at 15, 19, 25, 31, and 37 weeks' gestation in a sample of 84 pregnant women. ASD symptoms were assessed in their 5-year old children with the Social Communication Questionnaire (SCQ). Fetal exposure to lower levels of maternal cortisol was associated with higher levels of ASD symptoms among boys only. The observed hypocortisolemic profile exhibited by these mothers may indicate a risk factor that precedes the stress of caregiving for a child with ASD and may not be solely a consequence of the stress of caregiving as previously thought. Further, these findings confirm the value of examining prenatal hormone exposures as predictors of ASD risk and support the premise that altered prenatal steroid exposures may play a role in the etiology of ASD.

Oxytocin and vasopressin increase male-directed threats and vocalizations in female macaques

In a previous study, we reported that intranasal delivery of both oxytocin (OT) and arginine vasopressin (AVP) to male macaques relaxes spontaneous social interactions, flattens the existing dominance hierarchy, and increases behavioral synchrony with other monkeys. Here we report that intranasal OT and AVP administration modulates the behaviors of female macaque monkeys, but in robustly different ways from males. Most notably, both neuropeptides increase threatening and vocalization behaviors of females when they encounter males, and these behaviors effectively increase the social status of females over males. While OT and AVP heighten the confrontational nature of intersexual encounters, both peptides relax interactions between females. Finally, as previously reported for males, treating an individual female monkey with OT or AVP significantly modulates the behavior of her non-treated partner. Together, these findings show that OT and AVP can either inhibit or promote aggression, depending on sex and behavioral context, and call for a more careful, systematic examination of the functions of these neuropeptides in both sexes, especially in the context of therapeutics for human social disorders.

Sex differences in psychomotor development during the preschool period: A longitudinal study of the effects of environmental factors and of emotional, behavioral, and social functioning

We sought to determine the extent to which sex differences in psychomotor development during the preschool period can be explained by differential exposure to environmental factors and/or differences in emotional, behavioral, or social functioning. Children from the EDEN mother-child cohort were assessed for language, gross motor, and fine motor skills at 2, 3, and 5-6 years of age using parental questionnaires and neuropsychological tests. Structural equation models examining the associations between sex and language, gross motor, and fine motor skills at 2, 3, and 5-6 years were performed while adjusting for a broad range of pre- and postnatal environmental factors as well as emotional, behavioral and socialization difficulties. Girls (n = 492) showed better fine motor skills than boys (n = 563) at 2 years (Cohen's d = 0.67 in the fully adjusted models), at 3 years (d = 0.72), and to a lesser extent at 5-6 years (d = 0.29). Girls also showed better language skills at 2 years (d = 0.36) and 3 years (d = 0.37) but not at 5-6 years (d = 0.04). We found no significant differences between girls and boys in gross motor skills at 2, 3, or 5-6 years. Similar results were found in the models unadjusted and adjusted for pre- and postnatal environmental factors as well as emotional, behavioral, and socialization difficulties. Our findings are consistent with the idea that sex differences in fine motor and language skills at 2 and 3 years of age are not explained by differential exposure to environmental factors or by sex differences in emotional, behavioral, or social functioning.

Social status and prenatal testosterone exposure assessed via second-to-fourth digit ratio affect 6-9-year-old children's prosocial choices

Prosocial behaviour (i.e., voluntary behaviour intended to benefit another) seems to be fully developed in children by the age of 6 years. However, questions about which factors modify prosocial behaviour at that age remain understudied. Here we used a resource allocation paradigm to test prosocial behaviour in 6-9-year-old school children. They could decide between a "selfish" (i.e., one sticker for themselves) and a "prosocial" option (i.e., one sticker for themselves and one for the receiver) and we tested whether friendship, social status and prenatal androgen exposure (approximated by the 2nd to 4th digit ratio; 2D:4D) influenced children's prosocial choices. We found that children behaved prosocially, and that their prosocial tendencies were negatively correlated with prenatal androgen exposure; i.e., children with high 2D:4D ratios (reflecting low prenatal androgen exposure) acted more prosocially than children with low 2D:4D ratios. Further, their social status in the classroom influenced their choices: children with fewer interaction partners chose the "prosocial" option more often than more 'popular' children. However, they did so irrespectively of whether they were paired with a recipient or not. Our results highlight the importance of considering social, as well as physiological factors when investigating prosocial behaviour in children.

The Interplay between Gaze Following, Emotion Recognition, and Empathy across Adolescence; a Pubertal Dip in Performance?

During puberty a dip in face recognition is often observed, possibly caused by heightened levels of gonadal hormones which in turn affects the re-organization of relevant cortical circuitry. In the current study we investigated whether a pubertal dip could be observed in three other abilities related to social information processing: gaze following, emotion recognition from the eyes, and empathizing abilities. Across these abilities we further explored whether these measurements revealed sex differences as another way to understand how gonadal hormones affect processing of social information. Results show that across adolescence, there are improvements in emotion recognition from the eyes and in empathizing abilities. These improvements did not show a dip, but are more plateau-like. The gaze cueing effect did not change over adolescence. We only observed sex differences in empathizing abilities, with girls showing higher scores than boys. Based on these results it appears that gonadal hormones are not exerting a unified influence on higher levels of social information processing. Further research should also explore changes in (visual) information processing around puberty onset to find a more fitted explanation for changes in social behavior across adolescence.

Developmental vitamin D deficiency and autism: Putative pathogenic mechanisms

Autism is a neurodevelopmental disease that presents in early life. Despite a considerable amount of studies, the neurobiological mechanisms underlying autism remain obscure. Both genetic and environmental factors are involved in the development of autism. Vitamin D deficiency is emerging as a consistently reported risk factor in children. One reason for the prominence now being given to this risk factor is that it would appear to interact with several other epidemiological risk factors for autism. Vitamin D is an active neurosteroid and plays crucial neuroprotective roles in the developing brain. It has important roles in cell proliferation and differentiation, immunomodulation, regulation of neurotransmission and steroidogenesis. Animal studies have suggested that transient prenatal vitamin D deficiency is associated with altered brain development. Here we review the potential neurobiological mechanisms linking prenatal vitamin D deficiency and autism and also discuss what future research targets must now be addressed.

Gaze Following is Related to the Broader Autism Phenotype in a Sex-Specific Way: Building the Case for Distinct Male and Female Autism Phenotypes

The search for a female autism phenotype is difficult, given the low diagnostic rates in females. Here, we studied potential sex differences in a core feature of autism, difficulty with eye gaze processing, among typically developing individuals who vary in the broad autism phenotype, which includes autistic-like traits that are common, continuously distributed, and similarly heritable in males and females. Participants viewed complex images of an actor in a naturalistic scene looking at one of many possible objects and had to identify the target gazed-at object. Among males, those high in autistic-like traits exhibited worse eye gaze following performance than did those low in these traits. Among females, eye gaze following behavior did not vary with autistic-like traits. These results suggest that deficient eye gaze following behavior is part of the broader autism phenotype for males, but may not be a part of the female autism phenotype.

Retinoic acid-related orphan receptor alpha (RORA) variants are associated with autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with various epidemiologic, genetic, epigenetic, and environmental factors being associated with it. The observed sex bias in ASD towards male has prompted investigators to propose sex-dependent mechanisms for ASD. Retinoic acid-related orphan receptor-alpha (RORA) is a new autism candidate gene that has been shown to be differentially regulated by male and female hormones. Previous studies have shown deregulation of its expression in the prefrontal cortex and the cerebellum of ASD patients. In the present study we aimed at identification of the possible associations between two functional polymorphisms in the RORA gene (rs11639084 and rs4774388) and the risk of ASD in 518 Iranian ASD patients and 472 age, gender, and ethnic-matched healthy controls by means of tetra primer-amplification refractory mutation system-PCR. The allele and genotype frequencies of rs11639084 were not significantly different between patients and controls. However, the allele frequencies of rs4774388 showed significant overrepresentation of T allele in patients compared with controls (P = 0.04, OR (95% CI) =1.21 (1.01-1.46)). The rs4774388-TT genotype was significantly higher in patients compared with controls and was associated with ASD risk in dominant inheritance model (P = 0.04, OR (95% CI) =0.77 (0.59-0.99)). Haplotype analysis showed significant association of two estimated blocks of rs11639084/ rs4774388 with ASD risk. Consequently, the present data provide further evidence for RORA participation in the pathogenesis of ASD.

Associations between fetal testosterone and pro-social tendencies, anxiety and autistic symptoms in Williams syndrome: a preliminary study

Objective: Fetal testosterone (fT) has organizational effects on the developing human nervous system and can be reliably estimated by the ratio between the length of the second and fourth digits - 2D:4D. Previous studies reported altered patterns of fT in some developmental disabilities (e.g. ASD) relative to typically developing individuals (TD). Williams syndrome (WS) is a rare genetic disorder characterized by exacerbated empathy and social approach and heightened anxiety. Recent reports also highlight the co-occurrence of significant levels of autistic symptoms. Despite constituting an interesting model to study androgenic contributions to social behavior, no studies have sought to explore fT in WS. The main aims of this preliminary study were two-fold: (a) to compare 2D:4D in WS and TD; (b) to analyze the pattern of associations between 2D:4D and hypersociability, affective and cognitive empathy, anxiety and autistic symptoms in WS. Methods: 2D:4D were measured from digital scans of the ventral surface of the right hand. Hypersociability, empathy, anxiety and autistic symptoms were obtained from parental reports. Results: There were no significant differences in 2D:4D between WS than TD. In WS lower fT (higher 2D:4D) was significantly associated with hypersociability and affective empathy, as well as marginally associated with anxiety/depression scores. In contrast, cognitive empathy was marginally and negatively associated with 2D:4D, while levels of autistic symptoms were unrelated with this measure. Conclusion: Our results suggest that fT may be implicated in the emergence of several cardinal features of WS, namely hypersociability, affective empathy and anxiety, but not in ASD symptoms.

Phenotypic integration mediated by hormones: associations among digit ratios, body size and testosterone during tadpole development

BACKGROUND

Developmental associations often explain phenotypic integration. The intersected hormonal regulation of ontogenetic processes fosters predictions of steroid-mediated phenotypic integration among sexually dimorphic traits, a statement defied by associations between classical dimorphism predictors (e.g. body size) and traits that apparently lack sex-specific functions (e.g. ratios between the lengths of Digits II and IV - 2D:4D). Developmental bases of female-biased 2D:4D have been identified, but these remain unclear for taxa presenting male-biased 2D:4D (e.g. anura). Here we propose two alternative hypotheses to investigate evolution of male-biased 2D:4D associated with sexually dimorphic body size using Leptodactylus frogs: I)'hypothesis of sex-specific digit responses' - Digit IV would be reactive to testosterone but exhibit responses in the opposite direction of those observed in female-biased 2D:4D lineages, so that Digit IV turns shorter in males; II) 'hypothesis of identity of the dimorphic digit'- Digit II would be the dimorphic digit.

RESULTS

We compiled the following databases using Leptodactylus frogs: 1) adults of two species from natural populations and 2) testosterone-treated L. fuscus at post-metamorphic stage. Studied traits seem monomorphic in L. fuscus; L. podicipinus exhibits male-biased 2D:4D. When present, 2D:4D dimorphism was male-biased and associated with dimorphic body size; sex differences resided on Digit II instead of IV, corroborating our 'hypothesis of identity of the dimorphic digit'. Developmental steroid roles were validated: testosterone-treated L. fuscus frogs were smaller and exhibited masculinized 2D:4D, and Digit II was the digit that responded to testosterone.

CONCLUSION

We propose a model where evolution of sexual dimorphism in 2D:4D first originates from the advent, in a given digit, of increased tissue sensitivity to steroids. Phenotypic integration with other sexually dimorphic traits would then occur through multi-trait hormonal effects during development. Such process of phenotypic integration seems fitness-independent in its origin and might explain several cases of steroid-mediated integration among sexually dimorphic traits.