CSF: cerebrospinal fluid; EVD: extraventricular drainage; APOE: apolipoprotein E; PTGDS: prostaglandin D2 synthase; miRNA: micro RNA; PCR: polymerase chain reaction; GAL: galanin; HSPA5: heat shock 70 kDa protein 5; WNT4: wingless-type MMTV integration site family, member 4; CNS: central nervous system; MMD: moyamoya disease. Here, APOE is linked to Moyamoya disease.