With more than 100 common gene variants recently implicated in schizophrenia and autism, the problem now is to pinpoint how they might change brain circuits. A promising new tool is a sort of budding brain in a dish. What’s amazing – eclipsing earlier “disease-in-a-dish” discoveries – is that, over weeks and months, differentiating cells in these “organoids” organize themselves according to the architecture that we see in a functioning human brain.
Two papers published this week in Nature provide the first maps of the molecular development of the human brain. Mapping brain development by changes in gene expression gives us a new level of precision and raises new possibilities for understanding the mechanisms of neurodevelopmental disorders.
Results of the two largest studies of their kind, to date, have identified new common gene variants associated with schizophrenia and bipolar disorder. The results implicate specific pathways and hold promise for development of new treatments.
In recent years, NIMH-supported researchers have discovered several genes that are associated with autism spectrum disorder (ASD), schizophrenia, attention deficit hyperactivity disorder, and bipolar disorder. Most of these genes were discovered either through a candidate gene approach comparing cases and controls or by looking for linkage to genetic variation associated with occurrence of the disease in a family. However, the genomic variants discovered to date can explain only a small fraction of the genetic risk. So where are the missing genetic signals for mental disorders?