Elevated levels of growth-related hormones in autism and autism spectrum disorder

On the Optimal Combination of Elliptically Distributed Biomarkers to Improve Diagnostic Accuracy

Diagnostic biomarkers play a critical role in biomedical research, particularly for the diagnosis and prediction of diseases, etc. To enhance diagnostic accuracy, extensive research about combining multiple biomarkers has been developed based on the multivariate normality, which is often not true in practice, as most biomarkers follow distributions that deviate from normality. While the likelihood ratio combination is recognized to be the optimal approach, it is complicated to calculate. To achieve a more accurate and effective combination of biomarkers, especially when these biomarkers deviate from normality, we propose using a receiver operating characteristic (ROC) curve methodology based on the optimal combination of elliptically distributed biomarkers. In this paper, we derive the ROC curve function for the elliptical likelihood ratio combination. Further, proceeding from the derived best combinations of biomarkers, we propose an efficient technique via nonparametric maximum likelihood estimate (NPMLE) to build empirical estimation. Simulation results show that the proposed elliptical combination method consistently provided better performance, demonstrating its robustness in handling various distribution types of biomarkers. We apply the proposed method to two real datasets: Autism/autism spectrum disorder (ASD) and neural tube defects (NTD). In both applications, the elliptical likelihood ratio combination improves the AUC value compared to the multivariate normal likelihood ratio combination and the best linear combination.

Insulin-Like Growth Factor 1 Has the Potential to Be Used as a Diagnostic Tool and Treatment Target for Autism Spectrum Disorders

Autism spectrum disorder (ASD), a heterogeneous group of neurodevelopmental disorders, is characterized by social impairment and repetitive and stereotypic behaviors. Because of the lack of approved laboratory diagnostic markers and effective therapeutic medications, it is one of the most challenging diseases. Therefore, it is urgent to explore potential diagnosis markers or therapeutic targets. Insulin-like growth factor 1 (IGF-1) is a neurotrophic growth factor that enhances brain development. IGF-1 levels in body fluids are lower in preschool children with ASD than in typically developing children, which may serve as a potential diagnostic marker. In various ASD models associated with genetic or environmental exposure, IGF-1 treatment can improve core symptoms or pathological changes, including neuronal development, neural cell survival, balance of synaptic excitation and inhibition, neuroimmunology, and oxidative stress status. In March 2023 an IGF-1 derivative was approved as the first drug for treating Rett syndrome, an ASD-related neurodevelopmental disorder, to improve fundamental symptoms such as social communication. Thus, in this review, we present accumulating evidence of altered IGF-1 levels in ASD patients and the possible mechanisms, as well as evidence that IGF-1 treatment improves the pathophysiology in various ASD models. IGF-1 has the potential to be an early diagnosis marker and an effective therapeutic for 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.

Likelihood ratio combination of multiple biomarkers via smoothing spline estimated densities

The diagnostic accuracy of multiple biomarkers in medical research is crucial for detecting diseases and predicting patient outcomes. An optimal method for combining these biomarkers is essential to maximize the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC). Although the optimality of the likelihood ratio has been proven by Neyman and Pearson, challenges persist in estimating the likelihood ratio, primarily due to the estimation of multivariate density functions. In this study, we propose a non-parametric approach for estimating multivariate density functions by utilizing Smoothing Spline density estimation to approximate the full likelihood function for both diseased and non-diseased groups, which compose the likelihood ratio. Simulation results demonstrate the efficiency of our method compared to other biomarker combination techniques under various settings for generated biomarker values. Additionally, we apply the proposed method to a real-world study aimed at detecting childhood autism spectrum disorder (ASD), showcasing its practical relevance and potential for future applications in medical research.

Mast Cells in Autism Spectrum Disorder-The Enigma to Be Solved?

Autism Spectrum Disorder (ASD) is a disturbance of neurodevelopment with a complicated pathogenesis and unidentified etiology. Many children with ASD have a history of "allergic symptoms", often in the absence of mast cell (MC)-positive tests. Activation of MCs by various stimuli may release molecules related to inflammation and neurotoxicity, contributing to the development of ASD. The aim of the present paper is to enrich the current knowledge on the relationship between MCs and ASD by discussing key molecules and immune pathways associated with MCs in the pathogenesis of autism. Cytokines, essential marker molecules for MC degranulation and therapeutic targets, are also highlighted. Understanding the relationship between ASD and the activation of MCs, as well as the involved molecules and interactions, are the main points contributing to solving the enigma. Key molecules, associated with MCs, may provide new insights to the discovery of drug targets for modeling inflammation in ASD.

[Biochemical markers of autism]

Autism spectrum disorder (ASD) is becoming an increasingly common disorder of the development of the nervous system in the modern world. The diagnosis is made based on observation of the patient's behavior, which significantly complicates the diagnosis and treatment of the disorder. The subjectivity of behavioral diagnostics dictates the need for the study of biomarkers of ASD. Over the past two decades, researchers have focused on identifying specific biological abnormalities in ASD that will help in the diagnosis of the disease. This review discusses the state of research on various biomarkers currently being developed for ASD.

The early life growth of head circumference, weight, and height in infants with autism spectrum disorders: a systematic review

BACKGROUNDS

The Autism spectrum disorder (ASD) prevalence has increased significantly over the past two decades. This review summarizes the current knowledge of the association between the early life growth of head circumference (HC), weight, and height with ASD in infants.

METHODS

PubMed, Scopus, Science Direct, and Google Scholar databases were searched up to November 2021 using relevant keywords. All original articles are written in English evaluating the early life growth of HC, weight, and height in infants with ASD were eligible for the present review.

RESULTS

Totally, 23 articles involving 4959 infants were included in this review. Of 13 studies that evaluated HC of infants at birth, 10 studies (83.33%) showed that the HC at the birth of autistic children was similar to that of the average found in the control group. Among 21 studies that evaluated the HC and weight status in infants, 19 studies (90.47%) showed that autistic children had larger HC and weight than the control group or abnormal acceleration of head growth during infancy. Height growth of infants was investigated in 13 studies, of which 10 cases (76.92%) reported that infants with ASD were significantly longer than control groups. Most of he included studies had a good quality.

CONCLUSIONS

The findings suggest that in infants with ASD, without the contribution of birth growth factors and sex of the child, the growth of HC, weight, and height probably was faster than in infants with normal development, in early life. Therefore, these measurements might be useful as initial predictive biomarkers for the risk of developing ASD.

The role of insulin/IGF1 signalling in neurodevelopmental and neuropsychiatric disorders - Evidence from human neuronal cell models

Insulin and insulin-like growth factor 1 (IGF1) signalling play a central role in the development and maintenance of neurons in the brain, and human neurodevelopmental as well as neuropsychiatric disorders have been linked to impaired insulin and IGF1 signalling. This review focuses on the impairments of the insulin and IGF1 signalling cascade in the context of neurodevelopmental and neuropsychiatric disorders, based on evidence from human neuronal cell models. Clear evidence was obtained for impaired insulin and IGF1 receptor downstream signalling in neurodevelopmental disorders, while the evidence for its role in neuropsychiatric disorders was less substantial. Human neuronal model systems can greatly add to our knowledge about insulin/IGF1 signalling in the brain, its role in restoring dendritic maturity, and complement results from clinical studies and animal models. Moreover, they represent a useful model for the development of new therapeutic strategies. Further research is needed to systematically investigate the exact role of the insulin/IGF1 signalling cascades in neurodevelopmental and neuropsychiatric disorders, and to elucidate the respective therapeutic implications.

The neurobiology of insulin-like growth factor I: From neuroprotection to modulation of brain states

After decades of research in the neurobiology of IGF-I, its role as a prototypical neurotrophic factor is undisputed. However, many of its actions in the adult brain indicate that this growth factor is not only involved in brain development or in the response to injury. Following a three-layer assessment of its role in the central nervous system, we consider that at the cellular level, IGF-I is indeed a bona fide neurotrophic factor, modulating along ontogeny the generation and function of all the major types of brain cells, contributing to sculpt brain architecture and adaptive responses to damage. At the circuit level, IGF-I modulates neuronal excitability and synaptic plasticity at multiple sites, whereas at the system level, IGF-I intervenes in energy allocation, proteostasis, circadian cycles, mood, and cognition. Local and peripheral sources of brain IGF-I input contribute to a spatially restricted, compartmentalized, and timed modulation of brain activity. To better define these variety of actions, we consider IGF-I a modulator of brain states. This definition aims to reconcile all aspects of IGF-I neurobiology, and may provide a new conceptual framework in the design of future research on the actions of this multitasking neuromodulator in the brain.

Nutritional Status and Feeding Behavior of Children with Autism Spectrum Disorder in the Middle East and North Africa Region: A Systematic Review

Autism spectrum disorder (ASD) in children is associated with increased risks of overweight/obesity and underweight, altered nutrient profile, and abnormal feeding behaviors. This systematic review aimed to elucidate the literature on the nutritional status of children with ASD in the Middle East North Africa (MENA) region, by providing a summary and assessment of the body of evidence. A systematic review of English and Arabic publications up to November 2020 was conducted of five databases in addition to the grey literature, which include a nutrition-related parameter, from both experimental and observational study designs. Children with ASD (ASD-C) between 2 and 19 years in the MENA Region were the target population. For risk of bias, the Academy of Nutrition and Dietetics' Quality Criteria Checklist (QCC) was adopted. The number of published articles was grossly limited. Forty-three articles were included, of which only four articles reported a low risk of bias; therefore, the results were interpreted in light of methodological limitations. Both overweight and underweight were common in ASD-C, although not consistently different than typically developing children. Nutrient inadequacies of energy, protein, omega-3, and others; deficiencies in serum iron indicators and calcium, as well as vitamins B12, B9, and D levels; and higher levels of homocysteine and omega-6/omega-3 ratios were reported. Feeding behavior problems were also common in ASD-C. Understanding nutritional requirements and food preferences can guide the planning of the appropriate comprehensive interventions for ASD-C. Various nutritional and behavioral concerns were identified in the included studies; however, they were subject to methodological weaknesses, which limited the generalizability of these results. Future research is warranted that must be directed to finding strong evidence using robust study designs on nutritional status and feeding behaviors of ASD-C, with a particular emphasis on the MENA Region.

BDNF, proBDNF and IGF-1 serum levels in naïve and medicated subjects with autism

Brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) promote the development and maintenance of neural circuits. Alterations in these factors might contribute to autism spectrum disorder (ASD). We asked whether serum BDNF, proBDNF, and IGF-1 levels are altered in an ASD population compared to controls. We measured serum BDNF, proBDNF, and IGF-1 immunoreactive protein in boys and girls aged 5–15 years old with mild to moderate ASD and non-autistic controls by ELISA. IGF-1 was increased in ASD serum compared to controls and was correlated with age and with CARS scores. Serum BDNF levels did not differ between groups, however, proBDNF serum levels were decreased in subjects with ASD compared to non-autistic controls. Medicated, but not unmedicated, ASD subjects exhibited lower serum proBDNF levels compared to controls, while neither IGF-1 nor BDNF levels differed between treatment groups. These data support the involvement of proBDNF and IGF-1 in the pathogenesis and treatment of autism.

Marginal, conditional, and pseudo likelihood ratio approaches for biomarker combination to predict a binary disease outcome

It is a common practice in public health research that multiple biomarkers are collected to diagnose or predict a disease outcome. A natural question is how to combine multiple biomarkers to improve the diagnostic accuracy. It has been shown by Neyman-Pearson lemma that the likelihood ratio statistic achieves the optimal AUC in theory. However, practical difficulty often lies in the estimation of the multivariate density functions. We propose three novel methods for the biomarker combination, with the idea of breaking down the joint densities to a series of univariate densities. The marginal likelihood ratio approach only assumes the marginal distribution of each biomarker. While the conditional likelihood ratio (CLR) and pseudo likelihood ratio (PLR) approaches assume the conditional distributions of a marker given others, and hence make use of the correlation structure to estimate the combination rules. The proposed methods make it much easier to assume and validate the univariate distributions of a biomarker than making multivariate distributional assumptions. Extensive simulation studies demonstrate that the CLR and the PLR approaches outperform many existing methods, and are therefore recommended for practical use. The proposed methods are motivated by and applied to a biomarker study to diagnose childhood autism/autism spectrum disorder.

Serum levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 in children with autism spectrum disorder

OBJECTIVES

To study the serum levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in children with autism spectrum disorder (ASD) and their association with the core symptoms of ASD.

METHODS

A total of 150 ASD children aged 2-7 years (ASD group) and 165 healthy children matched for age and sex (control group) who were recruited at the outpatient service of Chongqing Health Center for Women and Children were enrolled as subjects. Autism Behavior Checklist (ABC) and Childhood Autism Rating Scale (CARS) were used to evaluate the core symptoms of the ASD children. Chemiluminescence was used to measure the serum levels of IGF-1 and IGFBP-3 in both groups.

RESULTS

The ASD group had a significantly lower serum level of IGF-1 than the control group (P<0.05). The children with severe ASD had significantly lower serum levels of IGF-1 and IGFBP-3 than those with mild-to-moderate ASD (P<0.001). For the children aged 2-3 years, the ASD group had a significantly lower serum level of IGF-1 than the control group (P<0.05). Boys had a significantly lower serum level of IGF-1 than girls in both ASD and control groups (P<0.05). The serum levels of IGF-1 and IGFBP-3 were negatively correlated with the total score of CARS (r=-0.32 and -0.40 respectively, P<0.001).

CONCLUSIONS

The reduction in serum IGF-1 level in early childhood may be associated with the development of ASD, and the serum levels of IGF-1 and IGFBP-3 are associated with the core symptoms of ASD children.

Weight status and body composition analysis among Polish boys with autism spectrum disorders

Currently, autism spectrum disorders (ASD) are one of the main health care problems in both Poland and in other countries. There are limited studies on the physical growth and body composition among children and adolescents with ASD. Several studies have indicated that the prevalence of unhealthy weight is high among autistic patients. Therefore, the main aim of this study was to assess the prevalence of underweight, overweight and obesity of Polish boys with ASD and to analyse body composition.

A cross-sectional study was performed on 29 Polish boys aged 3–11 with autism. Anthropometric measurements were taken. Bioelectrical impedance analysis (BIA) was used to evaluate body composition. The percentile values and z-scores for body height, body weight and BMI were calculated. The CDC cut–points were used to determine weight status. Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) version 25.

16.1% autistic boys had z-scores for body weight above two standard deviations, 12.9% had z-scores for body height above two standard deviations and z-scores for BMI above two standard deviations were found in 19.4% of the boys. 13.8% of autistic boys were underweight, 48.3% had healthy weight, 20.7% were overweight, and 17.2% were obese. The mean value of body fat percentage was 18.46%, and 16.1% of the boys with ASD had higher than normal fat tissue.

There is a high prevalence of overweight and obesity among Polish boys with autism.

Effect of non-invasive brain stimulation on behavior and serum brain-derived neurotrophic factor and insulin-like growth factor-1 levels in autistic patients

Aberrant neural connectivity and intra-cortical inhibitory dysfunction are key features of autism. Non-invasive brain stimulation (NIBS) protocols have been proposed that modulate this aberrant plasticity. However, additional investigations are needed to evaluate the impact of this intervention on biological biomarkers of the disease. We recently demonstrated alterations in serum insulin-like growth factor-1 (IGF-1) and brain-derived neurotrophic factor (BDNF) immunoreactivity in subjects with autism compared to controls. The aim of this pilot study was to explore the change in serum levels of the neurotrophic factors BDNF and IGF-1 in patients undergoing NIBS therapy. Sixteen subjects with autism spectrum disorder (ASD) were tested 1 week before and 1 week after NIBS to determine the short-term outcome on behavior using the total score on the autism behavior checklist, autism treatment evaluation checklist, clinical global impression severity and the autism diagnostic interview. ASD subjects younger than 11 years old (n = 11) were treated with transcranial direct current stimulation (tDCS), and those 11 years and older (n = 5) were treated with repetitive transcranial magnetic stimulation (rTMS). Serum levels of BDNF and IGF-1 were evaluated by Enzyme-Linked Immuno-Sorbent Assay before and after the intervention with NIBS. A significant reduction in scores on the clinical behavioral scales was observed in patients treated with NIBS (ABC-T p = .002, CGI-S p = .008, ADI-T and ATEC-T p < .0001). There was a trend towards reduced serum BDNF levels after NIBS (p = .061), while there was no change in IGF-1 levels. These data support further studies on the potential of BDNF as a biomarker to measure the effectiveness of NIBS in autism.

Peripheral blood neurotrophic factor levels in children with autism spectrum disorder: a meta-analysis

Increasing evidence suggests that abnormal regulation of neurotrophic factors is involved in the etiology and pathogenesis of Autism Spectrum Disorder (ASD). However, clinical data on neurotrophic factor levels in children with ASD were inconsistent. Therefore, we performed a systematic review of peripheral blood neurotrophic factors levels in children with ASD, and quantitatively summarized the clinical data of peripheral blood neurotrophic factors in ASD children and healthy controls. A systematic search of PubMed and Web of Science identified 31 studies with 2627 ASD children and 4418 healthy controls to be included in the meta-analysis. The results of random effect meta-analysis showed that the peripheral blood levels of brain-derived neurotrophic factor (Hedges’ g = 0.302; 95% CI = 0.014 to 0.591; P = 0.040) , nerve growth factor (Hedges’ g = 0.395; 95% CI = 0.104 to 0.686; P = 0.008) and vascular endothelial growth factor (VEGF) (Hedges’ g = 0.097; 95% CI = 0.018 to 0.175; P = 0.016) in children with ASD were significantly higher than that of healthy controls, whereas blood neurotrophin-3 (Hedges’ g =  − 0.795; 95% CI =  − 1.723 to 0.134; P = 0.093) and neurotrophin-4 (Hedges’ g = 0.182; 95% CI =  − 0.285 to 0.650; P = 0.445) levels did not show significant differences between cases and controls. Taken together, these results clarified circulating neurotrophic factor profile in children with ASD, strengthening clinical evidence of neurotrophic factor aberrations in children with ASD.

Comparison of Serum VEGF, IGF-1, and HIF-1α Levels in Children with Autism Spectrum Disorder and Healthy Controls

The aim of this study was to determine whether serum VEGF, IGF-1, and HIF-1α levels differed between Autism Spectrum Disorder (ASD) patients and healthy controls. A total of 40 children with ASD and 40 healthy controls aged 4-12 years were included. Serum levels of VEGF, IGF-1, and HIF-1α were measured using commercial enzyme-linked immunosorbent assay kits. Serum IGF-1 levels were found to be statistically significantly higher in the ASD group than in the control group. Serum HIF-1α levels were borderline significantly lower in the ASD group. There was no statistically significant difference in serum VEGF levels between the two groups. IGF-1 and HIF-1α may play a potential role in the etiopathogenesis of ASD.

Effects of maternal immune activation in porcine transcript isoforms of neuropeptide and receptor genes

The prolonged effects of maternal immune activation in response stressors during gestation on the offspring's molecular pathways after birth are beginning to be understood. An association between maternal immune activation and neurodevelopmental and behavior disorders such as autism and schizophrenia spectrum disorders has been detected in long-term gene dysregulation. The incidence of alternative splicing among neuropeptides and neuropeptide receptor genes, critical cell-cell signaling molecules, associated with behavior may compromise the replicability of reported maternal immune activation effects at the gene level. This study aims to advance the understanding of the effect of maternal immune activation on transcript isoforms of the neuropeptide system (including neuropeptide, receptor and connecting pathway genes) underlying behavior disorders later in life. Recognizing the wide range of bioactive peptides and functional receptors stemming from alternative splicing, we studied the effects of maternal immune activation at the transcript isoform level on the hippocampus and amygdala of three-week-old pigs exposed to maternal immune activation due to viral infection during gestation. In the hippocampus and amygdala, 29 and 9 transcript isoforms, respectively, had maternal immune activation effects (P-value < 0.01). We demonstrated that the study of the effect of maternal immune activation on neuropeptide systems at the isoform level is necessary to expose opposite effects among transcript isoforms from the same gene. Genes were maternal immune activation effects have also been associated with neurodevelopmental and behavior disorders. The characterization of maternal immune activation effects at the transcript isoform level advances the understanding of neurodevelopmental disorders and identifies precise therapeutic targets.

Global prevalence of obesity, overweight and underweight in children, adolescents and adults with autism spectrum disorder, attention-deficit hyperactivity disorder: A systematic review and meta-analysis

Individuals with autism spectrum disorder (ASD) or attention-deficit hyperactivity disorder (ADHD) may have unhealthy bodyweight. This meta-analysis was performed to understand the weight status in individuals with ASD or ADHD. PubMed, Embase, Cochrane and ISI Web of Science databases were searched from inception until June 2020 to identify relevant studies. Prevalence estimates and their 95% confidence intervals (CIs) of obesity, overweight and underweight were separately pooled using random-effects models. A total of 95 studies were included in the meta-analysis. The pooled estimates of the prevalence of obesity, overweight and underweight were 21.8%, 19.8% and 6.4% in individuals with ASD and 14.7%, 20.9% and 4.0% in individuals with ADHD. In subgroup analyses, an increasing trend in the prevalence of unhealthy weight was observed from children aged 2 to 5 years to adults with ASD (obesity: from 16.7% to 31.3%, overweight: from 16.2% to 27.2%, underweight from 5.3% to 8.6%) and from children aged 6 to 12 years to adults with ADHD (obesity: from 13.5% to 19.3%, overweight: from 18.8% to 31.2%). The worrisome epidemic of obesity and overweight in individuals with ASD, ADHD highlighted the need for weight management.

Autism and Williams syndrome: Dissimilar socio-cognitive profiles with similar patterns of abnormal gene expression in the blood

LAY ABSTRACT

Autism spectrum disorders and Williams syndrome are complex cognitive conditions exhibiting quite opposite features in the social domain: whereas people with autism spectrum disorders are mostly hyposocial, subjects with Williams syndrome are usually reported as hypersocial. At the same time, autism spectrum disorders and Williams syndrome share some common underlying behavioral and cognitive deficits. It is not clear, however, which genes account for the attested differences (and similarities) in the socio-cognitive domain. In this article, we adopted a comparative molecular approach and looked for genes that might be differentially (or similarly) regulated in the blood of people with these conditions. We found a significant overlap between genes dysregulated in the blood of patients compared to neurotypical controls, with most of them being upregulated or, in some cases, downregulated. Still, genes with similar expression trends can exhibit quantitative differences between conditions, with most of them being more dysregulated in Williams syndrome than in autism spectrum disorders. Differentially expressed genes are involved in aspects of brain development and function (particularly dendritogenesis) and are expressed in brain areas (particularly the cerebellum, the thalamus, and the striatum) of relevance for the autism spectrum disorder and the Williams syndrome etiopathogenesis. Overall, these genes emerge as promising candidates for the similarities and differences between the autism spectrum disorder and the Williams syndrome socio-cognitive profiles.

Endocrinological Abnormalities in Autism

A number of chemical messengers, such as various hormones and hormone-like substances, along with neurotransmitters, such as serotonin, dopamine, and norepinephrine, are directly or indirectly linked with the encoding of social behavior via their action at the amygdala, hippocampus, and other related brain structures known to be involved in different aspects of social development. It is thought that any imbalance in the secretion and action of these chemicals may lead to defective or abnormal social behaviors that are the hallmarks of Autism Spectrum Disorders (ASDs). Many of the studies have described an association between ASDs and endocrine dysfunction, but have failed to establish a cause-effect connection between these 2 conditions. All together, the literature regarding the role of endocrine-related factors and ASDs is sparse and remains somewhat preliminary, controversial, and inconclusive. Thus, more research is needed in the future to shed more light on this topic.

Dysfunctional proteins in neuropsychiatric disorders: From neurodegeneration to autism spectrum disorders

Despite fundamental differences in disease course and outcomes, neurodevelopmental (autism spectrum disorders - ASD) and neurodegenerative disorders (Alzheimer's disease - AD and Parkinson's disease - PD) present surprising, common traits in their molecular pathomechanisms. Uncontrolled oligomerization and aggregation of amyloid β (Aβ), microtubule-associated protein (MAP) tau, or α-synuclein (α-syn) contribute to synaptic impairment and the ensuing neuronal death in both AD and PD. Likewise, the pathogenesis of ASD may be attributed, at least in part, to synaptic dysfunction; attention has also been recently paid to irregularities in the metabolism and function of the Aβ precursor protein (APP), tau, or α-syn. Commonly affected elements include signaling pathways that regulate cellular metabolism and survival such as insulin/insulin-like growth factor (IGF) - PI3 kinase - Akt - mammalian target of rapamycin (mTOR), and a number of key synaptic proteins critically involved in neuronal communication. Understanding how these shared pathomechanism elements operate in different conditions may help identify common targets and therapeutic approaches.

Effects of early life exposure to traffic-related air pollution on brain development in juvenile Sprague-Dawley rats

Epidemiological studies link traffic-related air pollution (TRAP) to increased risk for various neurodevelopmental disorders (NDDs); however, there are limited preclinical data demonstrating a causal relationship between TRAP and adverse neurodevelopmental outcomes. Moreover, much of the preclinical literature reports effects of concentrated ambient particles or diesel exhaust that do not recapitulate the complexity of real-world TRAP exposures. To assess the developmental neurotoxicity of more realistic TRAP exposures, we exposed male and female rats during gestation and early postnatal development to TRAP drawn directly from a traffic tunnel in Northern California and delivered to animals in real-time. We compared NDD-relevant neuropathological outcomes at postnatal days 51-55 in TRAP-exposed animals versus control subjects exposed to filtered air. As indicated by immunohistochemical analyses, TRAP significantly increased microglial infiltration in the CA1 hippocampus, but decreased astrogliosis in the dentate gyrus. TRAP exposure had no persistent effect on pro-inflammatory cytokine levels in the male or female brain, but did significantly elevate the anti-inflammatory cytokine IL-10 in females. In male rats, TRAP significantly increased hippocampal neurogenesis, while in females, TRAP increased granule cell layer width. TRAP had no effect on apoptosis in either sex. Magnetic resonance imaging revealed that TRAP-exposed females, but not males, also exhibited decreased lateral ventricular volume, which was correlated with increased granule cell layer width in the hippocampus in females. Collectively, these data indicate that exposure to real-world levels of TRAP during gestation and early postnatal development modulate neurodevelopment, corroborating epidemiological evidence of an association between TRAP exposure and increased risk of NDDs.

The risk of overweight and obesity in children with autism spectrum disorders: A systematic review and meta-analysis

Multiple studies have suggested that autism spectrum disorders seem to increase the risk of overweight and obesity. We examined the pooled prevalence and relative risk of developing overweight or obesity among children with autism spectrum disorders in a systematic review and meta-analysis. We searched PubMed, Scopus, ProQuest, and Web of Science databases and subsequently screened the records to identify studies that reported prevalence of overweight and/or obesity in children with ASD and matched groups of neurotypical children. DerSimonian-Laird random-effects meta-analyses were performed to examine pooled prevalence and relative risk of obesity in children with autism spectrum disorders using the "meta" package in R software. Among children with autism spectrum disorders, the prevalence of obesity was 22.2%. Children with ASD had a 41.1% greater risk (P = .018) of development of obesity. Non-Caucasian race, increasing age, female sex, and living in the United States emerged as positive moderators of the association between autism spectrum disorders and prevalence of overweight or obesity. Autism spectrum disorders seem to increase the risk of childhood obesity. Increased awareness of this association may allow the implementation of early interventions to reduce obesity and prevent potential deterioration of quality-of-life in this population.

Why are individuals with autism spectrum disorder at risk group for unhealthy weight?

Several studies have indicated that the prevalence of unhealthy body weight in individuals with autism spectrum disorder (ASD) is high. It is unclear whether factors related to the weight status of children and adolescents with ASD are the same or different from factors associated with the weight status of typically developing children (TDC). The objective of this review was to identify key factors associated with the higher rates of unhealthy weight observed in individuals with ASD and create a structural model, which could be used for future autism intervention research. This review summarizes the current state of knowledge on the genetic basis of obesity in ASD, special treatment (behavioral and medical, including diet and psychotropic medications), psychological (depression and anxiety) as well as somatic comorbid disorders such as feeding problems, sensory processing disorders, gastrointestinal problems and sleep disorders, physical activity and sedentary behaviors, loneliness and social isolation, and family functioning (maternal depression and stress).

Steroid Metabolites Support Evidence of Autism as a Spectrum

Objectives: It is common nowadays to refer to autism as a spectrum. Increased evidence of the involvement of steroid metabolites has been shown by the presence of stronger alterations in Kanner's syndrome compared with Asperger syndrome. Methods: 24 h urine samples were collected from 20 boys with Asperger syndrome, 21 boys with Kanner's syndrome, and identically sized control groups, each matched for age, weight, and height for comprehensive steroid hormone metabolite analysis via gas chromatography-mass spectrometry. Results: Higher levels of most steroid metabolites were detected in boys with Kanner's syndrome and Asperger syndrome compared to their matched controls. These differences were more pronounced in affected individuals with Kanner's syndrome versus Asperger syndrome. Furthermore, a specific and unique pattern of alteration of androsterone, etiocholanolone, progesterone, tetrahydrocortisone, and tetrahydrocortisol was identified in boys with Kanner's syndrome and Asperger syndrome. Interestingly, in both matched samples, only androsterone, etiocholanolone, progesterone, tetrahydrocortisone, tetrahydrocortisol, and 5a-tetrahydrocortisol groups were positively correlated. In the Asperger syndrome group, all metabolites showed a positive correlation. In the Kanner's syndrome group, 5-a tetrahydrocortisol with androsterone showed a positive correlation. Conclusions: Due to differences in the level of alteration, the premise that Asperger syndrome is on the mild side of the autism spectrum and that Kanner's syndrome is on the severe side is supported, but alteration patterns yield different phenotypic expressions.

Association between the methylation of six apoptosis‑associated genes with autism spectrum disorder

Excessive apoptosis hinders the process of brain maturation and is regarded as one of the principal risk factors for the development of autism spectrum disorder (ASD). The aim of the present study was to investigate the association between the methylation of six apoptosis‑associated genes [transforming growth factor β 1 (TGFB1), BCL2 associated X, apoptosis regulator, insulin like growth factor binding protein 3, protein kinase C β 1, presenilin 2 and C‑C motif chemokine ligand 2] and ASD. Using quantitative methylation‑specific polymerase chain reaction technology, DNA methylation levels were detected in 42 autistic and 26 control subjects. The logistic regression analysis results demonstrated that of the six genes, only TGFB1 was significantly hypomethylated in peripheral blood samples from children with autism compared with control samples (mean percentage of methylated reference, 0.011% vs. 0.019%; age‑adjusted P=0.028). In addition, TGFB1 methylation was identified to be positively associated with the interaction ability score from the Autism Behavior Checklist (r=0.452; P=0.035). These data suggested that decreased TGFB1 methylation may contribute to the development of ASD.

Skeletal Growth Dysregulation in Australian Male Infants and Toddlers With Autism Spectrum Disorder

Recent findings suggest that children with Autism Spectrum Disorder (ASD) are larger in size for head circumference (HC), height, and weight compared to typically developing (TD) children; however, little is known about their rate of growth, especially in height and weight. The current study aimed to: (a) confirm and extend upon previous findings of early generalized overgrowth in ASD; and (b) determine if there were any differences in the rate of growth between infants and toddlers with ASD compared to their TD peers. Measurements of HC, height, and weight were available for 135 boys with ASD and 74 TD boys, from birth through 3 years of age. Size and growth rate in HC, height, and weight were analyzed using a linear mixed-effects model. Infants with ASD were significantly smaller in size at birth for HC, body length, and weight compared to TD infants (all P < 0.05); however, they grew at a significantly faster rate in HC and height in comparison to the TD children (P < 0.001); there was no significant difference between the groups in growth rate for weight (P > 0.05). The results confirmed that male infants and toddlers with ASD exhibit skeletal growth dysregulation early in life. Autism Res 2018, 11: 846-856. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Recent findings suggest that infants with Autism Spectrum Disorder (ASD) are smaller in size at birth compared to typically developing infants but grow larger than their peers during the first year. Little is known about their rate of growth, especially for height and weight. Our findings confirmed that infants with ASD are smaller in size at birth for head circumference (HC), height, and weight, but grow at a faster rate in HC and height than their peers from birth to 3 years.

Acetylcholine Modulates the Hormones of the Growth Hormone/Insulinlike Growth Factor-1 Axis During Development in Mice

Pituitary growth hormone (GH) and insulinlike growth factor (IGF)-1 are anabolic hormones whose physiological roles are particularly important during development. The activity of the GH/IGF-1 axis is controlled by complex neuroendocrine systems including two hypothalamic neuropeptides, GH-releasing hormone (GHRH) and somatostatin (SRIF), and a gastrointestinal hormone, ghrelin. The neurotransmitter acetylcholine (ACh) is involved in tuning GH secretion, and its GH-stimulatory action has mainly been shown in adults but is not clearly documented during development. ACh, together with these hormones and their receptors, is expressed before birth, and somatotroph cells are already responsive to GHRH, SRIF, and ghrelin. We thus hypothesized that ACh could contribute to the modulation of the main components of the somatotropic axis during development. In this study, we generated a choline acetyltransferase knockout mouse line and showed that heterozygous mice display a transient deficit in ACh from embryonic day 18.5 to postnatal day 10, and they recover normal ACh levels from the second postnatal week. This developmental ACh deficiency had no major impact on weight gain and cardiorespiratory status of newborn mice. Using this mouse model, we found that endogenous ACh levels determined the concentrations of circulating GH and IGF-1 at embryonic and postnatal stages. In particular, serum GH level was correlated with brain ACh content. ACh also modulated the levels of GHRH and SRIF in the hypothalamus and ghrelin in the stomach, and it affected the levels of these hormones in the circulation. This study identifies ACh as a potential regulator of the somatotropic axis during the developmental period.

Drug treatment of autism spectrum disorder and its comorbidities in children and adolescents

Autism spectrum disorder (ASD) is a complex, multifactorial disorder, the prevalence of which is rising. Specific biomarkers are yet to be identified for the classic ASD phenotypes, so despite treatment advances, most interventions focus on the comorbid disorders of ASD and have little impact on the underlying pathogenesis of the disorder. This article describes drug treatments that target the core symptoms of ASD and its comorbid conditions in children and adolescents. Difficulties and challenges encountered when treating the most frequent comorbidities are discussed, with emphasis on the safety, tolerability and efficacy of medications. In view of its widespread use, complementary and alternative medicine is also described.

Microglia M2A Polarization as Potential Link between Food Allergy and Autism Spectrum Disorders

Atopic diseases are frequently co-morbid with autism spectrum disorders (ASD). Allergic responses are associated with an activation of mast cells, innate lymphoid cells, and Th2 cells. These cells produce type-2 cytokines (IL4 and IL13), which stimulate microglia and macrophages to adopt a phenotype referred to as ‘alternative activation’ or ‘M2A’. M2A-polarized macrophages and microglia play a physiological role in tissue repair by secreting growth factors such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1. In ASD there is evidence for increased type-2 cytokines, microglia activation, M2A polarization, and increased levels of growth factors. In neurons, these growth factors drive a signal transduction pathway that leads to activation of the enzyme mammalian Target of Rapamycin (mTOR), and thereby to the inhibition of autophagy. Activation of mTOR is an effect that is also common to several of the genetic forms of autism. In the central nervous system, redundant synapses are removed via an autophagic process. Activation of mTOR would diminish the pruning of redundant synapses, which in the context of ASD is likely to be undesired. Based on this line of reasoning, atopic diseases like food allergy, eczema or asthma would represent risk factors for autism spectrum disorders.

A semiparametric method for comparing the discriminatory ability of biomarkers subject to limit of detection

Receiver operating characteristic curves and the area under the curves (AUC) are often used to compare the discriminatory ability of potentially correlated biomarkers. Many biomarkers are subject to limit of detection due to the instrumental limitation in measurements and may not be normally distributed. Standard parametric methods assuming normality can lead to biased results when the normality assumption is violated. We propose new estimation and inference procedures for the AUCs of biomarkers subject to limit of detection by using the semiparametric transformation model allowing for heteroscedasticity. We obtain the nonparametric maximum likelihood estimators by maximizing the likelihood for the observed data with limit of detection. The proposed estimators are shown to be consistent, asymptotically normal, and asymptotically efficient. Additionally, we propose a Wald type test statistic to compare the AUCs of 2 potentially correlated biomarkers with limit of detection. Extensive simulation studies demonstrate that the proposed method is robust to nonnormality while performing as well as its parametric counterpart when the normality assumption is true. An application to an autism study is provided.

Decreased levels of serum fibroblast growth factor-2 in children with autism spectrum disorder

The neurodevelopment and functioning of the central nervous system, and especially the cerebral cortex, have basic importance to understand neuropsychiatric disorders like autism. Fibroblast growth factor-2 (FGF-2) plays a very important role in the development and functioning of the cortex. FGF-2 is related to developmental processes in the central nervous system such as neurogenesis, migration, differentiation and survival. This study researched the serum FGF-2 levels in children with autism spectrum disorder (ASD). With this aim, 60 ASD children and 40 healthy controls were compared. We applied a sociodemographic form and the Childhood Autism Rating Scale (CARS) to each subject with their family to assess the severity of autism. Additionally, all subjects had routine laboratory tests performed. Serum samples were studied with ELISA. The results found that serum FGF-2 levels were statistically significantly low in the patient group compared to the healthy control group (p value 0.003). Additionally there was a statistically significant negative correlation identified between serum FGF-2 levels and CARS score for all subjects (r = -0.300; p = 0.02). In conclusion, FGF-2 may contribute to the etiopathogenesis of ASD.

Insulin-Like Growth Factors in the Pathogenesis of Neurological Diseases in Children

Insulin-like growth factors play a key role for neuronal growth, differentiation, the survival of neurons and synaptic formation. The action of IGF-1 is most pronounced in the developing brain. In this paper we will try to give an answer to the following questions: Why are studies in children important? What clinical studies in neonatal asphyxia, infantile spasms, progressive encephalopathy-hypsarrhythmia-optical atrophy (PEHO) syndrome, infantile ceroid lipofuscinosis (INCL), autistic spectrum disorders (ASD) and subacute sclerosing encephalopathy (SSPE) have been carried out? What are IGF-based therapeutic strategies? What are the therapeutic approaches? We conclude that there are now great hopes for the therapeutic use of IGF-1 for some neurological disorders (particularly ASD).

Serum Levels of Insulin-Like Growth Factor-1 and Obsessive-Compulsive Disorder: A Case-Control Study

BACKGROUND/AIMS

Recent findings suggest an involvement of insulin-like growth factor-1 (IGF-1) in the pathogenesis of many psychiatric disorders; however, there is a lack of data regarding IGF-1 in patients with obsessive-compulsive disorder (OCD). The aims of the present study were (1) to analyze putative alterations of IGF-1 serum content in patients with OCD compared to patients with major depressive disorder (MDD) and healthy controls, and (2) to analyze putative changes of IGF-1 levels during drug treatment in subjects with OCD compared to patients with MDD.

METHODS

We recruited 40 OCD patients, 37 MDD patients, and 43 healthy controls. All participants were adults. Serum IGF-1 levels were measured by the ELISA method on venous blood samples collected at baseline and after 10 ± 1 weeks of drug treatment.

RESULTS

IGF-1 levels were increased in OCD patients compared to controls (149.9 ± 60.2 vs. 121.2 ± 51.6 ng/ml; p = 0.040). No correlations were observed between baseline IGF-1 levels, clinical features, and response to treatment at follow-up in OCD or MDD patients. No changes in serum IGF-1 were observed after drug treatment.

CONCLUSION

Our results show for the first time that serum IGF-1 levels are altered in patients with OCD. Further research on the role of IGF-1 in OCD is warranted.

Treatment of autistic spectrum disorder with insulin-like growth factors

There are no treatments for the core symptoms of autistic spectrum disorder (ASD), but there is now more knowledge on emerging mechanisms and on mechanism-based therapies. In autism there are altered synapses: genes affected are commonly related to synaptic and immune function. Dysregulation of activity-dependent signaling networks may have a key role the etiology of autism. There is an over-activation of IGF-AKT-mTor in autism spectrum disorders. Morphological and electro-physiological defects of the cerebellum are linked to system-wide ASD-like behavior defects. The molecular basis for a cerebellar contribution has been demonstrated in a mouse model. These have led to a potential mechanism-based use of drug targets and mouse models. Neurotrophic factors are potential candidates for the treatment. Insulin-like growth factor-1 (IGF-1) is altered in autism. It reduces neuro-inflammation: by causing changes of cytokines such as IL-6 and microglial function. IGF-1 reduces the defects in the synapse. It alleviates NMDA-induced neurotoxicity via the IGF-AKT-mTor pathway in microglia. IGF-1 may rescue function in Rett syndrome and ASD caused by changes of the SCHANK3 gene. There are recently pilot studies of the treatment of Rett syndrome and of SCHANK3 gene deficiency syndromes. The FDA has granted Orphan drug designations for Fragile X syndrome, SCHANK3 gene deficiency syndrome and Rett syndrome.

Insulin-Like Growth Factor 1 and Related Compounds in the Treatment of Childhood-Onset Neurodevelopmental Disorders

Insulin-Like Growth Factor 1 (IGF-1) is a neurotrophic polypeptide with crucial roles to play in Central Nervous System (CNS) growth, development and maturation. Following interrogation of the neurobiology underlying several neurodevelopmental disorders and Autism Spectrum Disorders (ASD), both recombinant IGF-1 (mecasermin) and related derivatives, such as (1-3)IGF-1, have emerged as potential therapeutic approaches. Clinical pilot studies and early reports have supported the safety/preliminary efficacy of IGF-1 and related compounds in the treatment of Rett Syndrome, with evidence mounting for its use in Phelan McDermid Syndrome and Fragile X Syndrome. In ASD, clinical trials are ongoing. Here, we review the role of IGF-1 in the molecular etiologies of these conditions in addition to the accumulating evidence from early clinical studies highlighting the possibility of IGF-1 and related compounds as potential treatments for these childhood-onset neurodevelopmental disorders.

Association between IRS1 Gene Polymorphism and Autism Spectrum Disorder: A Pilot Case-Control Study in Korean Males

The insulin-like growth factor (IGF) pathway is thought to play an important role in brain development. Altered levels of IGFs and their signaling regulators have been shown in autism spectrum disorder (ASD) patients. In this study, we investigated whether coding region single-nucleotide polymorphisms (cSNPs) of the insulin receptor substrates (IRS1 and IRS2), key mediators of the IGF pathway, were associated with ASD in Korean males. Two cSNPs (rs1801123 of IRS1, and rs4773092 of IRS2) were genotyped using direct sequencing in 180 male ASD patients and 147 male control subjects. A significant association between rs1801123 of IRS1 and ASD was shown in additive (p = 0.022, odds ratio (OR) = 0.66, 95% confidence interval (CI) = 0.46–0.95) and dominant models (p = 0.013, OR = 0.57, 95% CI = 0.37–0.89). Allele frequency analysis also showed an association between rs1801123 and ASD (p = 0.022, OR = 0.66, 95% CI = 0.46–0.94). These results suggest that IRS1 may contribute to the susceptibility of ASD in Korean males.

Overweight and Obesity in a Sample of Children With Autism Spectrum Disorder

OBJECTIVE

To determine the prevalence of overweight/obese status in children with autism spectrum disorders (ASD), identify associated characteristics, and develop a model to predict weight status.

METHODS

The prevalence of overweight and obesity was determined in 2769 children with ASD enrolled in the Autism Speaks Autism Treatment Network, a collaboration of 17 academic centers, and compared with a national sample matched for age, sex, and race. Associations in the ASD sample between weight status and demographic and clinical variables, such as age, race, head circumference, and adaptive functioning, were tested using ordinal logistic regression. The accuracy of a final model that predicted weight status based on early life variables was evaluated in a validation sample.

RESULTS

The prevalence of overweight and obesity were 33.9% and 18.2%, respectively; ASD was associated with a higher risk of obesity (but not overweight) relative to the national sample (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.05-1.28; P = .003). In the adjusted analysis, overweight/obese status was significantly associated with Hispanic ethnicity (OR, 1.99; 95% CI, 1.37-2.89), parental high school education (OR, 1.56; 95% CI, 1.09-2.21), high birth weight (OR, 1.56; 95% CI, 1.11-2.18), macrocephaly (OR, 4.01; 95% CI, 2.96-5.43), and increased somatic symptoms (OR, 1.41; 95% CI, 1.01-1.95). A prediction model designed to have high sensitivity predicted low risk of overweight/obesity accurately, but had low positive predictive value.

CONCLUSIONS

The prevalence of obesity in children with ASD was greater than a national sample. Independent associations with increased weight status included known risk factors and macrocephaly and increased level of somatic symptoms. A model based on early life variables accurately predicted low risk of overweight/obesity.

Opposite risk patterns for autism and schizophrenia are associated with normal variation in birth size: phenotypic support for hypothesized diametric gene-dosage effects

Opposite phenotypic and behavioural traits associated with copy number variation and disruptions to imprinted genes with parent-of-origin effects have led to the hypothesis that autism and schizophrenia share molecular risk factors and pathogenic mechanisms, but a direct phenotypic comparison of how their risks covary has not been attempted. Here, we use health registry data collected on Denmark's roughly 5 million residents between 1978 and 2009 to detect opposing risks of autism and schizophrenia depending on normal variation (mean ± 1 s.d.) in adjusted birth size, which we use as a proxy for diametric gene-dosage variation in utero. Above-average-sized babies (weight, 3691-4090 g; length, 52.8-54.3 cm) had significantly higher risk for autism spectrum (AS) and significantly lower risk for schizophrenia spectrum (SS) disorders. By contrast, below-average-sized babies (2891-3290 g; 49.7-51.2 cm) had significantly lower risk for AS and significantly higher risk for SS disorders. This is the first study directly comparing autism and schizophrenia risks in the same population, and provides the first large-scale empirical support for the hypothesis that diametric gene-dosage effects contribute to these disorders. Only the kinship theory of genomic imprinting predicts the opposing risk patterns that we discovered, suggesting that molecular research on mental disease risk would benefit from considering evolutionary theory.

Autism with intellectual disability related to dynamics of head circumference growth during early infancy

BACKGROUND

It is not yet definitively known whether dynamic features of head circumference growth are associated with autism. To address this issue, we carried out a nested matched case-control study using data from national well baby clinics in Finland; autism cases were identified from the Finnish Hospital and Outpatient Discharge Registry.

METHODS

A nonparametric Bayesian method was used to construct growth velocity trajectories between birth and 2 years of age in autism cases and matched control subjects (n = 468 in main analyses, 1:1 matched control subjects). Estimates of odds ratios for autism risk in relation to the growth velocities were obtained using conditional logistic regression.

RESULTS

Growth velocity of head circumference at 3 months of age, adjusting for gestational age at birth and maternal age, is significantly associated with autism (p = .014); the finding was observed in subjects with comorbid intellectual disability (ID) (p = .025) but not in those without ID (p = .15). Height growth velocity among subjects with autism and without ID is significantly associated with autism at 6 months (p = .007), and weight growth velocity at 18 months without ID (p = .02) and 24 months without ID (p = .042) and with ID (p = .037).

CONCLUSIONS

Acceleration in head circumference growth is associated with autism with comorbid ID at 3 months but not subsequently. This association is unrelated to acceleration in height and weight, which are not strongly associated with autism until after 6 months.

The dwarf phenotype in GH240B mice, haploinsufficient for the autism candidate gene Neurobeachin, is caused by ectopic expression of recombinant human growth hormone

Two knockout mouse models for the autism candidate gene Neurobeachin (Nbea) have been generated independently. Although both models have similar phenotypes, one striking difference is the dwarf phenotype observed in the heterozygous configuration of the GH240B model that is generated by the serendipitous insertion of a promoterless human growth hormone (hGH) genomic fragment in the Nbea gene. In order to elucidate this discrepancy, the dwarfism present in this Nbea mouse model was investigated in detail. The growth deficiency in Nbea^+/− mice coincided with an increased percentage of fat mass and a decrease in bone mineral density. Low but detectable levels of hGH were detected in the pituitary and hypothalamus of Nbea^+/− mice but not in liver, hippocampus nor in serum. As a consequence, several members of the mouse growth hormone (mGH) signaling cascade showed altered mRNA levels, including a reduction in growth hormone-releasing hormone mRNA in the hypothalamus. Moreover, somatotrope cells were less numerous in the pituitary of Nbea^+/− mice and both contained and secreted significantly less mGH resulting in reduced levels of circulating insulin-like growth factor 1. These findings demonstrate that the random integration of the hGH transgene in this mouse model has not only inactivated Nbea but has also resulted in the tissue-specific expression of hGH causing a negative feedback loop, mGH hyposecretion and dwarfism.

Early generalized overgrowth in autism spectrum disorder: prevalence rates, gender effects, and clinical outcomes

OBJECTIVE

Although early head and body overgrowth have been well documented in autism spectrum disorder (ASD), their prevalence and significance remain unclear. It is also unclear whether overgrowth affects males and females differentially, and whether it is associated with clinical outcomes later in life.

METHOD

To evaluate prevalence of somatic overgrowth, gender effects, and associations with clinical outcomes, head circumference, height, and weight measurements were collected retrospectively between birth and 2 years of age in toddlers with ASD (n = 200) and typically developing (TD; n = 147) community controls. Symptom severity, verbal, and nonverbal functioning were assessed at 4 years.

RESULTS

Abnormalities in somatic growth in infants with ASD were consistent with early generalized overgrowth (EGO). Boys but not girls with ASD were larger and exhibited an increased rate of extreme EGO compared to community controls (18.0% versus 3.4%). Presence of a larger body at birth and postnatal overgrowth were associated independently with poorer social, verbal, and nonverbal skills at 4 years.

CONCLUSION

Although early growth abnormalities in ASD are less common than previously thought, their presence is predictive of lower social, verbal, and nonverbal skills at 4 years, suggesting that they may constitute a biomarker for identifying toddlers with ASD at risk for less-optimal outcomes. The results highlight that the search for mechanisms underlying atypical brain development in ASD should consider factors responsible for both neural and nonneural tissue development during prenatal and early postnatal periods, and can be informed by the finding that early overgrowth may be more readily observed in males than in females with ASD.

Making progress in autism drug discovery

Currently, there are still just two medications approved by the U.S. FDA to treat the irritability that is often found in children with autism spectrum disorder (ASD). Furthermore, there are no drugs approved that treat the core symptoms of ASD. And while many drugs have had good outcomes in preclinical animal models, they have been met with very little success in human clinical trials. There are several factors likely contributing to this problem starting with the heterogeneity within the ASD phenotype. It is therefore important that researchers develop their knowledge about the neurobiological basis of ASD as well as possible subgroups within the disorder, based on either specific behavioral profiles or biological pathways. Furthermore, the development of valid biological markers will allow researchers to use more than parent or teacher reports to determine if a treatment is effective. This author believes that there a good chance of finding effective pharmacological treatments for the core symptoms of ASD with this increased knowledge of the biology and etiology.

Altered expression of Alzheimer's disease-related genes in the cerebellum of autistic patients: a model for disrupted brain connectome and therapy

Autism and Alzheimer's disease (AD) are, respectively, neurodevelopmental and degenerative diseases with an increasing epidemiological burden. The AD-associated amyloid-β precursor protein-α has been shown to be elevated in severe autism, leading to the 'anabolic hypothesis' of its etiology. Here we performed a focused microarray analysis of genes belonging to NOTCH and WNT signaling cascades, as well as genes related to AD and apoptosis pathways in cerebellar samples from autistic individuals, to provide further evidence for pathological relevance of these cascades for autism. By using the limma package from R and false discovery rate, we demonstrated that 31% (116 out of 374) of the genes belonging to these pathways displayed significant changes in expression (corrected P-values <0.05), with mitochondria-related genes being the most downregulated. We also found upregulation of GRIN1, the channel-forming subunit of NMDA glutamate receptors, and MAP3K1, known activator of the JNK and ERK pathways with anti-apoptotic effect. Expression of PSEN2 (presinilin 2) and APBB1 (or F65) were significantly lower when compared with control samples. Based on these results, we propose a model of NMDA glutamate receptor-mediated ERK activation of α-secretase activity and mitochondrial adaptation to apoptosis that may explain the early brain overgrowth and disruption of synaptic plasticity and connectome in autism. Finally, systems pharmacology analyses of the model that integrates all these genes together (NOWADA) highlighted magnesium (Mg(2+)) and rapamycin as most efficient drugs to target this network model in silico. Their potential therapeutic application, in the context of autism, is therefore discussed.