Compared to a control group, those with 22q had overall significantly lower brain volumes, as well as lower volumes in specific structures including the thalamus, hippocampus and amygdala, compared with the control group. They also had higher volumes in several brain structures. The magnitude of these abnormalities, especially in those 22q individuals with psychosis, was larger than is typical in many other common psychiatric conditions.
About a quarter of people with 22q develop schizophrenia or experience psychotic symptoms, so studying the syndrome provides a unique window into how such psychiatric problems develop over time. But the disorder is rare - about one in 4,000 people have it, making it tough for researchers at any single institution to study the syndrome.
To address that problem, the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) consortium launched a new working group to study 22q using data collected by researchers across the U.S., Canada, Europe, Australia and South America. ENIGMA is led by Paul Thompson, associate director of the Mark and Mary Stevens Neuroimaging and Informatics Institute (INI) at the Keck School of Medicine of USC, who has been uniting researchers around the world to pool data and insights on rare diseases for a decade.
"We have pieced together many of the major research centers studying 22q11DS around the world to create the largest-ever neuroimaging study of the disorder," said Christopher Ching, a postdoctoral researcher at the INI and first author of the study.
To get a clear picture of the brain abnormalities associated with schizophrenia in individuals with 22q, the study's authors examined magnetic resonance imaging (MRI) scans from 533 people with the disorder and 330 healthy control subjects. Using advanced analytic techniques developed at the INI, the authors measured and mapped structural differences between the brains of the two groups.
Notably, the brain changes seen in people with 22q and psychosis significantly overlapped with the brain changes observed in previous neuroimaging studies of schizophrenia and other serious mental illnesses including bipolar disorder, major depression and obsessive-compulsive disorder.
"That's important because these overlapping brain signatures add evidence to support 22q11DS as a good model for understanding schizophrenia in the wider population," Ching said. "And thanks to these large ENIGMA studies, we now have a way to directly compare standardized brain markers across major psychiatric illnesses on an unprecedented scale."
MEDICA-tradefair.com; Source: University of Southern California