Polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome (PMSE) is a rare genetic disorder that was identified in an Old Order Mennonite pediatric population. It is characterized by abnormal brain development, an abnormally large brain, cognitive disability, and severe, therapy-resistant epilepsy. PMSE is caused by mutations in the gene STRADA. A team of researchers has now provided insight into how mutations in STRADA cause PMSE by analyzing a human PMSE brain and mice.