Bone microarchitecture in adolescent boys with autism spectrum disorder

Bone health in children and youth with ASD: a systematic review and meta-analysis

Higher risk of fracture reported in individuals with autism spectrum disorder (ASD) might be linked to poor bone health and development in childhood. This study aimed to systematically review studies comparing imaged bone outcomes between children with ASD and typically developing children (TDC) or reference data, and to perform a meta-analysis comparing commonly reported bone outcomes. We searched articles published since August 2020 from PubMed, Cochrane Library, Web of Science, EMBASE, and Scopus databases. We included studies comparing areal bone mineral density (aBMD) between children with ASD and TDC in the qualitative analysis (meta-analysis), and evaluated other imaged bone outcomes qualitatively. Seven publications were identified for the systematic review, and four studies were included in the meta-analysis. The meta-analysis indicated lower aBMD at the total body (standardized mean difference = - 0.77; 95% CI, - 1.26 to - 0.28), lumbar spine (- 0.69; - 1.00 to - 0.39), total hip (- 1.00; - 1.82 to - 0.17), and femoral neck (- 1.07; - 1.54 to - 0.60) in children with ASD compared to TDC. Based on our qualitative review, limited evidence suggested 13% lower bone mineral content at the total body and 10-20% lower cortical area, cortical and trabecular thickness, and bone strength at the distal radius and tibia in children with ASD. Children with ASD have lower aBMD at the total body, lumbar spine, and hip and femoral neck compared to TDC. Limited evidence also suggests deficits in bone mineral content, micro-architecture, and strength in children with ASD.

Altered Bone Status in Rett Syndrome

Rett syndrome (RTT) is a monogenic neurodevelopmental disorder primarily caused by mutations in X-linked MECP2 gene, encoding for methyl-CpG binding protein 2 (MeCP2), a multifaceted modulator of gene expression and chromatin organization. Based on the type of mutation, RTT patients exhibit a broad spectrum of clinical phenotypes with various degrees of severity. In addition, as a complex multisystem disease, RTT shows several clinical manifestations ranging from neurological to non-neurological symptoms. The most common non-neurological comorbidities include, among others, orthopedic complications, mainly scoliosis but also early osteopenia/osteoporosis and a high frequency of fractures. A characteristic low bone mineral density dependent on a slow rate of bone formation due to dysfunctional osteoblast activity rather than an increase in bone resorption is at the root of these complications. Evidence from human and animal studies supports the idea that MECP2 mutation could be associated with altered epigenetic regulation of bone-related factors and signaling pathways, including SFRP4/WNT/β-catenin axis and RANKL/RANK/OPG system. More research is needed to better understand the role of MeCP2 in bone homeostasis. Indeed, uncovering the molecular mechanisms underlying RTT bone problems could reveal new potential pharmacological targets for the treatment of these complications that adversely affect the quality of life of RTT patients for whom the only therapeutic approaches currently available include bisphosphonates, dietary supplements, and physical activity.

Nutritional Rickets Due to Severe Food Selectivity in Autism Spectrum Disorder

OBJECTIVE

Studies have detected differences in various measures of bone health between individuals with autism spectrum disorder (ASD) and their peers. However, these measures do not amount to direct clinical evidence of increased orthopedic pathology in this population. Some of the most compelling evidence to this effect comes from case reports of nutritional rickets in children with ASD. We report on 1 such case that, to our knowledge, is the first report of nutritional rickets in ASD necessitating corrective surgery.

METHODS

Case report, review of relevant literature, and implications for further research.

RESULTS

An 11-year-old girl with ASD was admitted for postoperative medical comanagement after successful repair of bilateral genu valgum (knock knees). On admission, the patient's mother reported that the patient was a "picky eater." No cause had been determined preoperatively, although the deformity had developed at 10 years of age, thereby qualifying as pathologic. The medical team considered rickets because of the patient's limited diet. Subsequent laboratory work demonstrated hypocalcemia, vitamin D deficiency, and secondary hyperparathyroidism. The patient was diagnosed with nutritional rickets due to inadequate vitamin D intake, a consequence of severe food selectivity associated with ASD.

CONCLUSION

This case exemplifies the extreme orthopedic and metabolic complications that can result from food selectivity in children with ASD, pointing to the need for further research into the prevalence and causes of orthopedic pathology and nutritional rickets in this population. The case also underscores the need for evidence-based guidelines to prevent orthopedic pathology in children with ASD.

Bone Health in Childhood Chronic Disease

Many children with chronic disease are now surviving into adulthood. As a result, there is a growing interest in optimizing bone health early in the disease course with the dual goals of improving quality of life during childhood and reducing life-long fracture risk. Risk factors for impaired bone health in these children include immobility, nutritional deficiency, exposure to bone toxic therapies, hormonal deficiencies affecting growth and pubertal development, and chronic inflammation. This review focuses on the chronic diseases of childhood most commonly associated with impaired bone health. Recent research findings and clinical practice recommendations, when available, for specific disorders are summarized.

Effects of Neurological Disorders on Bone Health

Neurological diseases, particularly in the context of aging, have serious impacts on quality of life and can negatively affect bone health. The brain-bone axis is critically important for skeletal metabolism, sensory innervation, and endocrine cross-talk between these organs. This review discusses current evidence for the cellular and molecular mechanisms by which various neurological disease categories, including autoimmune, developmental, dementia-related, movement, neuromuscular, stroke, trauma, and psychological, impart changes in bone homeostasis and mass, as well as fracture risk. Likewise, how bone may affect neurological function is discussed. Gaining a better understanding of brain-bone interactions, particularly in patients with underlying neurological disorders, may lead to development of novel therapies and discovery of shared risk factors, as well as highlight the need for broad, whole-health clinical approaches toward treatment.

Comprehensive Analysis of RNA-Seq Gene Expression Profiling of Brain Transcriptomes Reveals Novel Genes, Regulators, and Pathways in Autism Spectrum Disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with deficits in social communication ability and repetitive behavior. The pathophysiological events involved in the brain of this complex disease are still unclear.

METHODS

In this study, we aimed to profile the gene expression signatures of brain cortex of ASD patients, by using two publicly available RNA-seq studies, in order to discover new ASD-related genes.

RESULTS

We detected 1567 differentially expressed genes (DEGs) by meta-analysis, where 1194 were upregulated and 373 were downregulated genes. Several ASD-related genes previously reported were also identified. Our meta-analysis identified 235 new DEGs that were not detected using the individual RNA-seq studies used. Some of those genes, including seven DEGs (PAK1, DNAH17, DOCK8, DAPP1, PCDHAC2, and ERBIN, SLC7A7), have been confirmed in previous reports to be associated with ASD. Gene Ontology (GO) and pathways analysis showed several molecular pathways enriched by the DEGs, namely, osteoclast differentiation, TNF signaling pathway, complement and coagulation cascade. Topological analysis of protein-protein interaction of the ASD brain cortex revealed proteomics hub gene signatures: MYC, TP53, HDAC1, CDK2, BAG3, CDKN1A, GABARAPL1, EZH2, VIM, and TRAF1. We also identified the transcriptional factors (TFs) regulating DEGs, namely, FOXC1, GATA2, YY1, FOXL1, USF2, NFIC, NFKB1, E2F1, TFAP2A, HINFP.

CONCLUSION

Novel core genes and molecular signatures involved with ASD were identified by our meta-analysis.

Nutritional and environmental contributions to Autism Spectrum Disorders: Focus on nutrigenomics as complementary therapy

The prevalence of autism spectrum disorders (ASD) has risen sharply in the last 30 years, posing a major public health concern and a big emotional and financial challenge for families. While the underlying causes remain to be fully elucidated, evidence shows moderate genetic heritability contribution, but heavy environmental influence. Over the last decades, modern lifestyle has deeply changed our eating, rest, and exercise habits, while exposure to air, water, and food chemical pollution has increased due to indiscriminate use of pesticides, food additives, adjuvants, and antibiotics. The result is a drastic change in the quality of our energy source input, and an overload for antioxidant and detoxification pathways that compromises normal metabolism and homeostasis. Current research shows high prevalence of food selectivity and/or food allergy among children with autism, resulting in essential micronutrient deficits that may trigger or aggravate physical and cognitive symptoms. Nutrigenomics is an emerging discipline that focuses on genotype-micronutrient interaction, and a useful approach to tailor low risk, personalized interventions through diet and micronutrient supplementation. Here, we review available literature addressing the role of micronutrients in the symptomatology of ASD, the metabolic pathways involved, and their therapeutic relevance. Personalized and supervised supplementation according to individual needs is suggested as a complement of traditional therapies to improve outcome both for children with autism and their families.

Pharmacological, non-pharmacological and stem cell therapies for the management of autism spectrum disorders: A focus on human studies

In the last decade, the prevalence of autism spectrum disorders (ASD) has dramatically escalated worldwide. Currently available drugs mainly target some co-occurring symptoms of ASD, but are not effective on the core symptoms, namely impairments in communication and social interaction, and the presence of restricted and repetitive behaviors. On the other hand, transplantation of hematopoietic and mesenchymal stem cells in ASD children has been shown promising to stimulate the recruitment, proliferation, and differentiation of tissue-residing native stem cells, reducing inflammation, and improving some ASD symptoms. Moreover, several comorbidities have also been associated with ASD, such as immune dysregulation, gastrointestinal issues and gut microbiota dysbiosis. Non-pharmacological approaches, such as dietary supplementations with certain vitamins, omega-3 polyunsaturated fatty acids, probiotics, some phytochemicals (e.g., luteolin and sulforaphane), or overall diet interventions (e.g., gluten free and casein free diets) have been considered for the reduction of such comorbidities and the management of ASD. Here, interventional studies describing pharmacological and non-pharmacological treatments in ASD children and adolescents, along with stem cell-based therapies, are reviewed.

Beyond the brain: A multi-system inflammatory subtype of autism spectrum disorder

An immune-mediated subtype of autism spectrum disorder (ASD) has long been hypothesized. This article reviews evidence from family history studies of autoimmunity, immunogenetics, maternal immune activation, neuroinflammation, and systemic inflammation, which suggests immune dysfunction in ASD. Individuals with ASD have higher rates of co-morbid medical illness than the general population. Major medical co-morbidities associated with ASD are discussed by body system. Mechanisms by which FDA-approved and emerging treatments for ASD act upon the immune system are then reviewed. We conclude by proposing the hypothesis of an immune-mediated subtype of ASD which is characterized by systemic, multi-organ inflammation or immune dysregulation with shared mechanisms that drive both the behavioral and physical illnesses associated with ASD. Although gaps in evidence supporting this hypothesis remain, benefits of this conceptualization include framing future research questions that will help define a clinically meaningful subset of patients and focusing clinical interactions on early detection and treatment of high-risk medical illnesses as well as interfering behavioral signs and symptoms across the lifespan.

Bone Mineral Density in Boys Diagnosed with Autism Spectrum Disorder: A Case-Control Study

This study compared bone mineral density (BMD) of the spine obtained by dual-energy X-ray absorptiometry (DEXA), nutritional status, biochemical markers, and gastrointestinal (GI) symptoms in 4-8 year old boys with Autism Spectrum Disorder (ASD) with a group of age-matched, healthy boys without ASD. Boys with ASD had significantly lower spine BMD compared to controls but this was not correlated with any biochemical markers, dietary intake of calcium and vitamin D, elimination diet status, or GI symptomology. Reduced BMD in 4-8 year old boys with ASD appears to involve factors other than nutrient intake and GI status, and requires further study.

Autism and heritable bone fragility: A true association?

Objectives

Osteogenesis Imperfecta (OI) is a heterogeneous condition mainly characterised by bone fragility; intelligence is reported to be normal. However, a minority of children seen also show symptomology consistent with an ‘Autism Spectrum Disorder’. A joint genetics and psychology research study was undertaken to identify these patients using ‘Gold Standard’ research tools: Autism Diagnostic Inventory Revised (ADI-R); Autism Diagnostic Observation Schedule (ADOS) and undertake genetic analyses in them.

Method

A cohort of n = 7 children with autistic traits and severe/complex OI were recruited to the study. The study was set-up to explore whether there was a genetic link between bone fragility and autism in a sub-set of patients with bone fragility identified with autism traits in our complex/severe OI clinic. This was not set-up as a prevalence study but rather an exploration of genetics in association with ADI/ADOS confirmed ASD and bone fragility.

ADI& ADOS

Standardised tools were used to confirm autism diagnosis. ADI and ADOS were completed by the Clinical Psychologist; ADI comprises a 93 item semi-structured clinical review with a diagnostic algorithm diagnosing Autism; ADOS is a semi-structured assessment of socialisation, communication and play/imagination which also provides a diagnostic algorithm.

Exome sequencing

In patients recruited, those that fulfilled research criteria for diagnosis of autism using above tools were recruited to trio whole exome sequencing (WES).

Results

one patient had compound heterozygous variants in NBAS; one patient had a variant in NRX1; one patient had a maternally inherited PLS3 variant; all the other patients in this cohort had pathogenic variants in COL1A1/COL1A2.

Conclusions

Although, not set out as an objective, we were able to establish that identifying autism had important clinical and social benefits for patients and their families in ensuring access to services, appropriate schooling, increased understanding of behaviour and support.

Lay summary

It is important for clinicians looking after children with brittle bone disease, also referred to as Osteogenesis Imperfecta (OI) to be aware of early features of developmental delay/autistic traits especially with severe forms of OI as the emphasis is on their mobility and bone health. Ensuring appropriate assessment and access to services early-on will enable these patients to achieve their potential. Further investigations of genomics in bone fragility in relation to autism are required and dual diagnosis is essential for high quality clinical and educational provision.

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Osteogenesis Imperfecta is the commonest form of heritable bone fragility disorder with an incidence of 1 in 15,000 live births

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Intelligence is usually reported to be normal; however, this study describes association of autistic traits with OI

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It is important to undertake autism assessments early in case of clinical suspicion of ASD as children with OI would benefit from early educational intervention

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Early identification and clarification of diagnosis of ASD in children with OI will ensure that children are able to achieve their full potential.

Nutrition and Bone Density in Boys with Autism Spectrum Disorder

BACKGROUND

Boys with autism spectrum disorder (ASD) have lower bone mineral density (BMD) than typically developing controls. Differences in diet and exercise may contribute to low BMD.

OBJECTIVE

Our aim was to examine macro- and micronutrient intakes and self-reported physical activity in boys with ASD compared to TDC and the relationship of these variables with BMD.

DESIGN/METHODS

We conducted a cross-sectional study of 49 boys (25 ASD, 24 typically developing controls) assessed for 3-day food records and physical activity records, and BMD of the whole body less head, hip, and spine using dual-energy x-ray absorptiometry. Fasting levels of 25(OH) vitamin D and calcium were obtained.

PARTICIPANTS

Participants were adolescent boys, aged 8 to 17 years, recruited from a clinic population (ASD) or community advertisements (ASD and typically developing controls) matched for age.

RESULTS

ASD participants were approximately 9 months younger than typically developing control participants on average. Body mass index and serum vitamin D and calcium levels were similar. Boys with ASD consumed 16% fewer calories, with a larger percentage obtained from carbohydrates, and 37% less animal protein and 20% less fat than typically developing controls. A lower proportion of ASD participants were categorized as "very physically active" (27% vs 79%; P<0.001). BMD z scores were 0.7 to 1.2 standard deviations lower in ASD than typically developing controls at all locations. Higher animal protein, calcium, and phosphorus intakes were associated positively with bone density measures in boys with ASD.

CONCLUSIONS

Compared to typically developing controls, boys with ASD had lower protein, calcium, and phosphorus intakes, activity levels, and BMD z scores at the lumbar spine, femoral neck, total hip, and whole body less head. Protein, calcium, and phosphorus intakes were associated positively with BMD.

Calcium and Vitamin D Supplementation in Boys with Risperidone-Induced Hyperprolactinemia: A Randomized, Placebo-Controlled Pilot Study

BACKGROUND

The chronic use of antipsychotics has been associated with impaired bone mineralization, partially mediated by hyperprolactinemia. We examined if calcium and vitamin D supplementation promote bone mineral accrual in boys with risperidone-induced hyperprolactinemia.

METHODS

Between February 2009 and November 2013, medically healthy, 5- to 17-year-old boys were enrolled in a 36-week double-blind, placebo-controlled study, examining the skeletal effects of supplementation with 1250 mg calcium carbonate and 400 IU of vitamin D3 in risperidone-induced hyperprolactinemia. Anthropometric, dietary, physical activity, and psychiatric assessments were conducted at baseline and week 18 and 36. Plasma prolactin and vitamin D concentrations were measured at baseline and week 36. Total body less head bone mineral content (BMC) and radius trabecular bone mineral density (BMD) were measured at baseline, week 18, and week 36, using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Linear mixed-effects regression analysis examined the longitudinal effect of treatment on skeletal outcomes.

RESULTS

Forty-seven boys (mean age: 11.0 ± 2.6 years) were randomized and 38 completed the study. At study entry, the average dietary calcium intake was below the recommended limit, but the average vitamin D concentration was normal. Calcium and vitamin D supplementation failed to significantly increase BMC or trabecular BMD. It also failed to affect several other skeletal and anthropometric outcomes, including plasma vitamin D concentration.

CONCLUSIONS

In this 9-month long pilot study, supplementation with a modest dose of calcium and vitamin D did not increase bone mass accrual in risperidone-treated boys with hyperprolactinemia. Alternative approaches should be investigated to optimize bone health in this population to prevent future morbidity and premature mortality. ClinicalTrials.gov Identifier: NCT00799383.

Bone Mass in Boys with Autism Spectrum Disorder

To examine bone mass in children and adolescents with autism spectrum disorders (ASD). Risperidone-treated 5 to 17 year-old males underwent anthropometric and bone measurements, using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Multivariable linear regression analysis models examined whether skeletal outcomes differed among participants with (n = 30) versus without ASD (n = 156). After adjusting for potential covariates, having ASD was associated with significantly lower trabecular bone mineral density and bone strength at the radius, and with marginally lower total body less head bone mineral content (p < 0.09). No differences at the lumbar spine were observed. ASD are associated with lower bone mass. Future studies should investigate interventions to optimize skeletal health in ASD.

Skeletal Site-specific Changes in Bone Mass in a Genetic Mouse Model for Human 15q11-13 Duplication Seen in Autism

Children suffering from autism have been reported to have low bone mineral density and increased risk for fracture, yet the cellular origin of the bone phenotype remains unknown. Here we have utilized a mouse model of autism that duplicates 6.3 Mb region of chromosome 7 (Dp/+) corresponding to a region of chromosome 15q11-13, duplication of which is recurrent in humans to characterize the bone phenotype. Paternally inherited Dp/+ (patDp/+) mice showed expected increases in the gene expression in bone, normal postnatal growth and body weight acquisition compared to the littermate controls. Four weeks-old patDp/+ mice develop a low bone mass phenotype in the appendicular but not the axial skeleton compared to the littermate controls. This low bone mass in the mutant mice was secondary to a decrease in the number of osteoblasts and bone formation rate while the osteoclasts remained relatively unaffected. Further in vitro cell culture experiments and gene expression analysis revealed a major defect in the proliferation, differentiation and mineralization abilities of patDp/+ osteoblasts while osteoclast differentiation remained unchanged compared to controls. This study therefore characterizes the structural and cellular bone phenotype in a mouse model of autism that can be further utilized to investigate therapeutic avenues to treat bone fractures in children with autism.