Examples of such conditions include: pineal cyst, old infarctions from ACTA2 mutation-related cerebral vasculopathy, posterior reversible encephalopathy syndrome, old brain injury, ventriculomegaly, arachnoid cyst, heterotopia, prior hemorrhage, Chiari I malformation, cooling post hypoxic-ischemic encephalopathy, tuberous sclerosis, headaches, epilepsy, congenital heart disease, trauma, and others. The gene discussed is ACTA2; the disease is arachnoid cyst.