Volumetric alterations in the basal ganglia in autism Spectrum disorder: A systematic review

INTRODUCTION

Recent research indicates that some brain structures show alterations in conditions such as Autism Spectrum Disorder (ASD). Among them, are the basal ganglia that are involved in motor, cognitive and behavioral neural circuits.

OBJECTIVE

Review the literature that describes possible volumetric alterations in the basal ganglia of individuals with ASD and the impacts that these changes have on the severity of the condition.

METHODOLOGY

This systematic review was registered in the design and reported according to the PRISMA Items and registered in PROSPERO (CRD42023394787). The study analyzed data from published clinical, case-contemplate, and cohort trials. The following databases were consulted: PubMed, Embase, Scopus, and Cochrane Central Register of Controlled Trials, using the Medical Subject Titles (MeSH) "Autism Spectrum Disorder" and "Basal Ganglia". The last search was carried out on February 28, 2023.

RESULTS

Thirty-five eligible articles were collected, analyzed, and grouped according to the levels of alterations.

CONCLUSION

The present study showed important volumetric alterations in the basal ganglia in ASD. However, the examined studies have methodological weaknesses that do not allow generalization and correlation with ASD manifestations.

Motor difficulties in 16p11.2 copy number variation

The rare genetic variants 16p11.2 duplication and 16p11.2 deletion have opposing effects on brain structure and function, yet are associated with broadly similar clinical phenotypes that include autism, intellectual impairment, psychiatric illness, and motor difficulties. In recent years, studies have identified subtle distinctions between the phenotypic effects of 16p11.2 duplication and 16p11.2 deletion with respect to patterns of autism, intellectual impairment, and psychiatric illness. However, although divergent phenotypic findings in some motor domains have been reported, no study has yet made a comprehensive comparison of motor difficulties between 16p11.2 deletion and 16p11.2 duplication carriers to elucidate points of convergence and divergence. We sought to make such a comparison in a group of 133 16p11.2 deletion carriers, 122 duplication carriers, and 388 familial controls, hypothesizing that motor impairment would overall be greater in deletion than duplication carriers. In a series of regression models, we found that 16p11.2 deletion status tended to predict greater impairment along indices of gross motor function, but less impairment along indices of fine motor function. These findings point to a potential pattern of performance difficulties that could be investigated in future studies. Elucidating motor differences between 16p11.2 duplication and 16p11.2 deletion carriers may help in understanding the complex effect of 16p11.2 copy number variation and other rare genetic causes of autism.

The use of noninvasive brain stimulation techniques in autism spectrum disorder

Noninvasive brain stimulation (NIBS) techniques, including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), have recently emerged as alternative, nonpharmacological interventions for a variety of psychiatric, neurological, and neurodevelopmental conditions. NIBS is beginning to be applied in both research and clinical settings for the treatment of core and associated symptoms of autism spectrum disorder (ASD) including social communication deficits, restricted and repetitive behaviors, irritability, hyperactivity, depression and impairments in executive functioning and sensorimotor integration. Though there is much promise for these targeted device-based interventions, in other disorders (including adult major depressive disorder (MDD) and obsessive compulsive disorder (OCD) where rTMS is FDA cleared), data on the safety and efficacy of these interventions in individuals with ASD is limited especially in younger children when neurodevelopmental interventions typically begin. Most studies are open-label, small scale, and/or focused on a restricted subgroup of individuals with ASD. There is a need for larger, randomized controlled trials that incorporate neuroimaging in order to develop predictive biomarkers of treatment response and optimize treatment parameters. We contend that until such studies are conducted, we do not have adequate estimates of the safety and efficacy of NIBS interventions in children across the spectrum. Thus, broad off-label use of these techniques in this population is not supported by currently available evidence. Here we discuss the existing data on the use of NIBS to treat symptoms related to ASD and discuss future directions for the field.

Psychopharmacological treatments in Down syndrome and autism spectrum disorder: State of the research and practical considerations

Individuals with Down syndrome (DS) or Autism Spectrum Disorder (ASD), and especially those with both DS and co-occurring ASD (DS + ASD) commonly display behavioral and psychiatric symptoms that can impact quality of life and places increased burden on caregivers. While the mainstay of treatment in DS and ASD is focused on educational and behavioral therapies, pharmacological treatments can be used to reduce symptom burden. There is a paucity of evidence and limited clinical trials in DS and DS + ASD. Some scientific evidence is available, primarily in open label studies and case series that can guide treatment choices. Additionally, clinical decisions are often extrapolated from evidence and experience from those with ASD, or intellectual disability in those without DS. This article reviews current research in pharmacological treatment in DS, ASD, and DS + ASD, reviews co-occurring neurodevelopmental and mental health diagnoses in individuals with DS + ASD across the lifespan, and describes practical approaches to psychopharmacological management.

Case reports of two siblings with autism spectrum disorder and 15q13.3 deletions

BACKGROUND

Copy number variations (CNVs) have been implicated in psychiatric and neurodevelopmental disorders. Especially, 15q13.3 deletions are strongly associated with autism spectrum disorder (ASD), intellectual disability (ID), schizophrenia (SCZ), attention deficithyperactivity disorder (ADHD), and mood disorder.

CASE PRESENTATION

We present two siblings with ASD. They had a father with bipolar disorder (BD). Patient 1 is a 21-year-old female with ASD and mild ID, who had language delay and repetitive behavior in childhood, social difficulties, and refused to go to school because of bullying. She was hospitalized in a psychiatric hospital several times. Patient 2 is a 19-year-old male with ASD and ADHD. He did not have developmental delay, but had social difficulties and impulsiveness, then refused to go to school because of bullying. He was treated by a psychiatrist for anxiety and disrupted sleep rhythms. Array comparative genomic hybridization was performed for the siblings and parents. 15q13.3 deletions were detected in the siblings and their healthy mothers. No other pathogenic CNVs were detected. We performed whole-genome sequencing of the family and identified 13 rare missense variants in brain-expressed genes, which may be responsible for the phenotypic differences between the siblings and their mother.

CONCLUSIONS

This study shows incomplete penetrance and variable expressivity in 15q13.3 deletions. We detected second-hit variants that may explain the phenotypic differences within this family. In addition, detecting 15q13.3 deletions may lead to early diagnosis and a better prognosis with careful follow-up.

Association of maternal autoimmune disease and early childhood infections with offspring autism spectrum disorder: A population-based cohort study

The aim of this study was to examine potential synergistic effects between maternal autoimmune disease and early childhood infections and their association with autism spectrum disorder (ASD) in offspring. Both exposures have been associated with increased risk of ASD in previous studies, but potential synergistic effects remain underexplored. We conducted a population-based cohort study of singleton children born at term gestation (37-41 weeks) in New South Wales, Australia from January 2002 to December 2008. Maternal autoimmune diagnoses and childhood infections before age 2 years were identified from linked maternal and child hospital admissions, and ASD diagnoses by age 9 years were identified from linked disability services data. Multivariable logistic regression assessed the association between each exposure and ASD and additive interaction between exposures, controlling for potential confounders. A total of 18,451 children exposed to maternal autoimmune disease were propensity score matched (1:2) to 36,902 unexposed children. Any maternal autoimmune disease (adjusted odds ratio (aOR) 1.25, 95% confidence interval (CI) 1.07-1.47) and any childhood infection before age 2 years (aOR 1.38, 95% CI 1.15-1.67) were each associated with ASD. However, there was no evidence of additive interaction between the two exposures (relative excess risk due to interaction [RERI] 0.128, 95% CI -0.418-0.675) resulting in increased odds of ASD in offspring. Future studies could examine potential interactions between other sources of maternal immune activation and childhood infection and impact on ASD and other neurodevelopmental disorders.