Author Interviews, Autism, Genetic Research, JAMA, Schizophrenia / 30.01.2016
Multiple New Genes Affecting Developmental Brain Disorders Identified
MedicalResearch.com Interview with:
[caption id="attachment_21154" align="alignleft" width="171"]
Andrea J. Gonzalez-Mantilla, M.D.[/caption]
Andrea J. Gonzalez-Mantilla, M.D.
Postdoctoral Fellow
[caption id="attachment_21155" align="alignleft" width="163"]
Andres Moreno-De-Luca, M.D.[/caption]
Andres Moreno-De-Luca, M.D.
Investigator I
Autism & Developmental Medicine Institute
Department of Radiology
Geisinger Health System
Danville, PA 17822
Medical Research: What is the background for this study? What are the main findings?
Response: Developmental brain disorders (DBD), such as autism, intellectual disability, and schizophrenia are a group of heterogeneous conditions characterized by deficits that affect multiple functional domains, such as cognition, behavior, communication, and motor skills. Previous studies provide strong evidence of common underlying molecular pathways and shared genetic causes among apparently different DBDs.
Large-scale genomic studies of individuals with developmental brain disorders have found that identifying multiple, independent de novo pathogenic loss-of-function (pLOF) variants in the same gene among unrelated individuals is a powerful statistical approach to reliably identify disease-causing genes. However, genomic data from smaller cohorts and case reports are not routinely pooled with data from larger studies. Moreover, most previous studies have been restricted to cohorts of individuals ascertained based on a single diagnosis (e.g., a study will focus on only individuals with a diagnosis of autism and not consider other genomic data from individuals with a different diagnosis). Therefore, genomic data from individuals across DBD are not being jointly analyzed in search of pLOF variants in the same gene that may help build evidence for a causative role in developmental brain disorders.
In this study, we carried out data mining of previously published data to identify genes related to the DBD phenotype. We expanded the aforementioned method and developed a multilevel data-integration approach, which capitalizes on three genotype-phenotype data sources:
(1) genomic data from structural and sequence pLOF variants,
(2) phenotype data from six apparently distinct DBD (autism, intellectual disability, epilepsy, schizophrenia, bipolar disorder and attention-deficit/hyperactivity disorder), and
(3) data from large scale studies, smaller cohorts, and case reports.
We identified 241 candidate genes for developmental brain disorders, including 17 genes that had not previously been associated with developmental brain disorders.
Andrea J. Gonzalez-Mantilla, M.D.[/caption]
Andrea J. Gonzalez-Mantilla, M.D.
Postdoctoral Fellow
[caption id="attachment_21155" align="alignleft" width="163"]
Andres Moreno-De-Luca, M.D.[/caption]
Andres Moreno-De-Luca, M.D.
Investigator I
Autism & Developmental Medicine Institute
Department of Radiology
Geisinger Health System
Danville, PA 17822
Medical Research: What is the background for this study? What are the main findings?
Response: Developmental brain disorders (DBD), such as autism, intellectual disability, and schizophrenia are a group of heterogeneous conditions characterized by deficits that affect multiple functional domains, such as cognition, behavior, communication, and motor skills. Previous studies provide strong evidence of common underlying molecular pathways and shared genetic causes among apparently different DBDs.
Large-scale genomic studies of individuals with developmental brain disorders have found that identifying multiple, independent de novo pathogenic loss-of-function (pLOF) variants in the same gene among unrelated individuals is a powerful statistical approach to reliably identify disease-causing genes. However, genomic data from smaller cohorts and case reports are not routinely pooled with data from larger studies. Moreover, most previous studies have been restricted to cohorts of individuals ascertained based on a single diagnosis (e.g., a study will focus on only individuals with a diagnosis of autism and not consider other genomic data from individuals with a different diagnosis). Therefore, genomic data from individuals across DBD are not being jointly analyzed in search of pLOF variants in the same gene that may help build evidence for a causative role in developmental brain disorders.
In this study, we carried out data mining of previously published data to identify genes related to the DBD phenotype. We expanded the aforementioned method and developed a multilevel data-integration approach, which capitalizes on three genotype-phenotype data sources:
(1) genomic data from structural and sequence pLOF variants,
(2) phenotype data from six apparently distinct DBD (autism, intellectual disability, epilepsy, schizophrenia, bipolar disorder and attention-deficit/hyperactivity disorder), and
(3) data from large scale studies, smaller cohorts, and case reports.
We identified 241 candidate genes for developmental brain disorders, including 17 genes that had not previously been associated with developmental brain disorders.
Dr. Richard Deth[/caption]
MedicalResearch.com Interview with:
Dr. Richard Deth PhD
Professor of Pharmacology
Department of Pharmaceutical Sciences
Nova Southeastern University
Medical Research: What is the background for this study?
Dr. Deth: Vitamin B12 plays a crucial role in regulating and promoting methylation reactions (the attachment of a carbon atom to molecules), including DNA methylation. Recent research has identified methylation of DNA and consequential changes in gene expression as crucial factors in brain development, as well as in memory formation and maintenance of brain function during aging. More specifically, the cause(s) of neurodevelopmental disorders such as autism remain obscure, although numerous studies have demonstrated oxidative stress and low plasma levels of the antioxidant glutathione (GSH) in autism.
Medical Research: What are the main findings?
Dr. Deth: We found that brain levels of vitamin B12, especially the methylation-regulating form known as methylB12, decrease significantly with age, even though blood levels don’t show a similar decrease. Importantly, much lower levels of methylB12 were found in subjects with autism and schizophrenia compared to normal subjects of a similar age. Animal studies showed that impaired GSH formation is associated with decreased brain B12 levels.
Dr. Diana Schendel[/caption]
MedicalResearch.com Interview with:
Diana Schendel, Professor MSO
Department of Public Health
Institute of Epidemiology and Social Medicine and
Department of Economics and Business National Centre for Register-based Research
Aarhus University
Denmark
Medical Research: What is the background for this study? What are the main findings?
Dr. Schende: Elevated mortality has been reported in persons with autism spectrum disorder (ASD), especially with comorbid epilepsy and intellectual disability. The effect of comorbidity on the risk for mortality in ASD, however, has not been rigorously examined in large, population-based studies. Our study aim was to investigate ASD mortality patterns overall and to assess the specific effects of comorbid mental, behavioral, and neurologic disorders on ASD mortality into young adulthood. Our study comprised a nation-wide Danish cohort of 1.9 million children of whom 20,492 were diagnosed with ASD. We observed 68 deaths in persons with ASD; 83% of the persons with ASD who died had comorbid mental/behavioral or neurologic disorders. The risk for mortality was two-fold higher in persons with
Dr. Chugani[/caption]
MedicalResearch.com Interview with:
Diane C. Chugani, PhD
Director, Nemours Neuroscience Research
Nemours—AI DuPont Hospital for Children
Wilmington, DE 19803
Medical Research: What is the background for this study? What are the main findings?
Dr. Chugani: This clinical trial was performed at 5 sites throughout the country and was lead by our team at Wayne State University and Children’s Hospital of Michigan in Detroit. The study was sponsored by the National Institutes of Health through an Autism Centers of Excellence Network grant. Based upon our previous PET scanning studies showing low serotonin synthesis in the brains of young children with autism, we tested whether the serotonin-like drug buspirone would be beneficial in treating young children with Autism Spectrum Disorder. We found that low doses of buspirone were effective in reducing repetitive behaviors with no significant side effects in this group of children.
Dr. Kenworthy[/caption]
MedicalResearch.com Interview with:
Lauren Kenworthy, PhD
Associate professor of Neurology, Pediatrics, and Psychiatry
George Washington University School of Medicine
Director of the Center for Autism Spectrum Disorders
Children’s National Health System
Medical Research: What is the background for this study? What are the main findings?
Dr. Kenworthy: Connectivity among brain regions may account for variability in autism outcomes not explained by age or behavioral measures, according to a study. We have previously shown that behavioral assessments of intelligence, baseline adaptive behavior and executive functions in people with autism can explain some of the variation in outcomes and function, but we have not been able to explain all of the variance in outcome (e.g. Pugliese et al 2015a, 2015b).
In this study, we found that 44% of the study group experienced significant change in scores on adaptive behavior between the initial scan and follow-up. Connectivity between three resting-state networks, including the salience network, the default-mode network, and the frontoparietal task control network, was linked not only to future autistic behaviors but also to changes in autistic and adaptive behaviors over the post-scan period. Further, connectivity involving the salience network and associated brain regions was associated with improvement in adaptive behaviors, with 100% sensitivity and around 71% precision.
















