Copy Number Variations

Using Extended Pedigrees to Identify Novel Autism Apectrum Disorder (ASD) Candidate Genes

Source: 
Human Genetics
Date Published: 
November 29, 2014
Abstract: 

Copy number variations are known to play a role in autism spectrum disorders. In a novel approach to study CNVs that may be present in family members, scientists look at genes in multiple generations of families affected with or without ASD as well as other psychiatric disorders. In one family, a part of chromosome 11 jumped out as being important for autism and what is known as the ‘broader autism phenotype’. (This is when a person does not have a diagnosis but meets some of the criteria for ASD.) This region contains genes for mitochondrial function and detoxification, but was found in the only family where the specific mutation was passed on beyond just parent to child. This shows that the genetic risk factors are complex and not even the same within the same family.

Whole-Genome Sequencing Reveals New Types of Autism Risk

Source: 
Simons Foundation Autism Research Initiative
Date Published: 
October 20, 2014
Abstract: 

Much of the genetic risk for autism may reside in regulatory regions of the genome, hidden from traditional methods of sequencing analysis. That's the upshot of preliminary results from three studies presented at the 2014 American Society of Human Genetics Annual Meeting in San Diego. Together, the findings from these new studies show the promise of looking for autism risk in unusual places.

Large Study Underscores Role of Gene Copy Number in Autism

Source: 
Simons Foundation Autism Research Initiative
Date Published: 
June 2, 2014
Abstract: 

People with autism tend to carry mutations that duplicate or delete several genes at once, according to a large study published in the American Journal of Human Genetics. Previous studies have shown that people with autism have more large deletions or duplications of DNA, also known as copy number variations (CNVs), than controls do. The new study, the largest to look at CNVs in people with autism thus far, confirms this finding. It also found that in people with autism, the CNVs are more likely to affect genes linked to intellectual disability and fragile X syndrome.

Convergence of Genes and Cellular Pathways Dysregulated in Autism Spectrum Disorders

Source: 
Cell
Date Published: 
April 24, 2014
Abstract: 

A substantial proportion of risk for developing autism spectrum disorders (ASD) resides in genes that are part of specific, interconnected biological pathways, according to researchers from the Icahn School of Medicine at Mount Sinai, who conducted a broad study of almost 2,500 families in the United States and throughout the world. The study was published in The American Journal of Human Genetics. The researchers reported numerous copy number variations (CNVS) affecting genes, and found that these genes are part of similar cellular pathways involved in brain development, synapse function and chromatin regulation. Individuals with ASD carried more of these CNVs than individuals in the control group, and some of them were inherited while others were only present in offspring with ASD.

Duplication of Chromosome 22 Region Thwarts Schizophrenia

Source: 
Simons Foundation Autism Research Institute
Date Published: 
January 2, 2014
Abstract: 

Carrying a duplication of the 22q11.2 chromosomal region may protect against schizophrenia, suggests a study published 12 November in Molecular Psychiatry. This is the first evidence of a genetic region that lowers the risk of a disorder rather than increases it. Deletion of this part of chromosome 22 is the strongest known risk factor for schizophrenia, and is also linked to autism, attention deficit hyperactivity disorder and anxiety in childhood. Various other copy number variations (CNVs), or stretches of a chromosome that are deleted or duplicated multiple times in the genome, have been linked to schizophrenia, autism and other neurological conditions. The new study is the first to pinpoint a CNV that lowers the risk of a disorder, however.

Brain Changes Precede Schizophrenia and Autism

Source: 
Nature
Date Published: 
December 18, 2013
Abstract: 

People who carry high-risk genetic variants for schizophrenia and autism have impairments reminiscent of disorders such as dyslexia, even when they do not yet have a mental illness, a new study has found. Researchers report that people with these copy number variants (CNVs) but no diagnosis of autism or a mental illness still show subtle brain changes and impairments in cognitive function. The findings offer a window into the brain changes that precede severe mental illness and hold promise for early intervention and even prevention, researchers say.

CNVs: Harbingers of a Rare Variant Revolution in Psychiatric Genetics.

Source: 
Cell
Date Published: 
March 16, 2012
Abstract: 

A proportion of risk for schizophrenia, bipolar disorder, and autism can be explained by rare mutations. Alleles can have specific effects on behavioral and neuroanatomical traits; however, expressivity is variable, particularly for neuropsychiatric phenotypes

Rate of De Novo Mutations and the Importance of Father’s Age to Disease Risk

Source: 
Nature
Date Published: 
August 23, 2012
Abstract: 

The diversity in mutation rate of SNP's is dominated by the age of the father at conception of the child. The effect is an increase of about two mutations per year.

New Gene Variants Linked to Autism

Source: 
Nature
Date Published: 
May 28, 2013
Abstract: 

A new study using families from the Autism Genetic Resource Exchange (AGRE) finds that individuals with autism are 20% more likely to have copy-number variations of specific genes.

Methylomic Analysis of Monozygotic Twins Discordant for Autism Spectrum Disorder and Related Behavioural Traits

Source: 
Molecular Psychiatry
Date Published: 
April 23, 2013
Abstract: 

This study suggests environmentally driven changes to the epigenome may contribute to the development of ASD and ASD-related behaviors. The study, which involved identical twins who were discordant for ASD and related traits, is the first large-scale examination of the role of genome-wide DNA methylation in ASD.