New Research Supported By Simons Foundation Points to Cellular Roots of Autism
Researchers at UC San Francisco have developed a new genetic model of autism, using neurons created in the lab from patients’ own skin cells. Their experiments suggest that abnormalities in the electrical firing of neurons may lead to behavioral and developmental symptoms in autism, while differences in neuron size and shape result in abnormalities in brain size that often accompany the disorder.
Scientists in the laboratory of Lauren Weiss, PhD, an associate professor of psychiatry and member of the Institute for Human Genetics at UCSF, looked at genetic mutations that cause either the deletion or duplication of a region of DNA on chromosome 16 that includes 29 genes implicated in important cellular functions in the brain. (Ordinarily, there are two copies of every gene, one on each chromosome, but deletions or duplications result in either one copy or three copies of the genes, respectively.)
In 2008, Weiss discovered that deletion or duplication of this region can result in autism. Epilepsy, psychiatric disorders, and other intellectual disabilities have also been linked to these mutations. In addition, deletion of the region causes macrocephaly — a disproportionately large brain — while duplication results in microcephaly, or an abnormally small brain. Autism is frequently accompanied by abnormal head size, leading to speculation that alterations in brain size could be a factor contributing to the disorder.
In the current study, published online December 8,2017 in Cell Reports, the researchers wanted to know how seemingly opposite mutations — either removing or adding a copy of the same 29 genes on chromosome 16 — could both result in autism. They also wanted to determine if micro- or macrocephaly could indeed be directly linked to autism...