JAN 28, 2016 2:01 PM PST

Gene Deletion Leads to IQ Drop and Potentially Autism

WRITTEN BY: Kara Marker
A missing copy of a region in chromosome 16, a mutation associated with autism, will always cause a 25-point drop in IQ, scientists say. Will the deletion cause autism every time? Not necessarily.
 
Autism is a spectrum disorder, meaning that a diagnosis could be either for a severe form or more mild form of the disease. Scientists believe multiple factors contribute to the development of autism. In addition to the 25-point drop in IQ that results from a deletion in chromosome 16, an abnormal addition in the same region causes a 16-point drop. Carriers of this mutation sometimes develop autism, but they also can show zero symptoms. Even more, there is a big difference in behavior between carriers with the same deletion or addition.
 

In the recent University of Montreal paper published in JAMA Psychiatry, scientists led a study where 700 family members were observed, each with at least one relative carrying the same genetic mutation on chromosome 16. The researchers found that even in study participants with the chromosome 16 deletion that appeared “normal,” they still had an IQ 25 points lower than their non-carrier relatives.
 
"No single mutation can cause the whole set of clinical signs shown by these [autism] patients," said geneticist Sébastien Jacquemont. He regularly diagnoses children with autism.
 
Just as someone with a chromosome 16 deletion is not necessarily destined to develop autism because of the multitude of other factors that make an impact, the deletion can also be the tipping point for someone who also has other predispositions to the disease. “Depending on the additional factors involved, a 25-point IQ drop can determine whether or not a person has crossed the threshold of 'intellectual disability,’” Jacquemont explained.
 
Prevalence of autism spectrum disorder is up from 6.7 percent of children in 2000 to 14.7 percent in 2010 (CDC).  However, also increasing since 2000 is the Autism and Developmental Disabilities Monitoring (ADDM) Network, a group of programs funded by the CDC to report the number of children in the United States with developmental disabilities like autism. Moreover, diagnoses are increasing because scientists are gaining more insight into the various sets of symptoms that indicate a child’s place on the autism spectrum and more agencies are keeping track of these children. The increase is not because of some environmental factor that is causing an increase in autism development.
 
 
Source: University of Montreal
 
About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
AUG 28, 2020
Cancer
Using CRISPR-Cas12a to Repair Hereditary Cancers in the Lab
AUG 28, 2020
Using CRISPR-Cas12a to Repair Hereditary Cancers in the Lab
Genome repair is one of the big-ticket research areas for the future of medicine. CRISPR-Cas9 systems can edit the genom ...
SEP 01, 2020
Genetics & Genomics
Women's Genes May Help Protect Against the Worst Alzheimer's Cases
SEP 01, 2020
Women's Genes May Help Protect Against the Worst Alzheimer's Cases
Women tend to get Alzheimer's more than men, but the female genome gives them some protection from the worst aspects of ...
SEP 04, 2020
Genetics & Genomics
Expanding Our View of How Gene Variants Affect Blood Cells
SEP 04, 2020
Expanding Our View of How Gene Variants Affect Blood Cells
Small changes in the sequences of some genes affect the characteristics of blood cells, and may contribute to an individ ...
SEP 10, 2020
Genetics & Genomics
Learning More About Racial Disparities in COVID-19
SEP 10, 2020
Learning More About Racial Disparities in COVID-19
While institutional racism in the healthcare system plays a major part, there seem to also be biological reasons why the ...
SEP 13, 2020
Genetics & Genomics
Men and Women Express Many Genes at Different Levels
SEP 13, 2020
Men and Women Express Many Genes at Different Levels
Most humans carry the same genes in their genome, but how are genes expressed differently in men and women?
OCT 09, 2020
Genetics & Genomics
Using CRISPR to Destroy Cancer Cells
OCT 09, 2020
Using CRISPR to Destroy Cancer Cells
Researchers have developed a way to selectively target certain cancer cells with CRISPR.
Loading Comments...