STMN1 and Hydrocephalus: While singular stathmin gene knockout led to no evident phenotypes (data not shown), we found that simultaneously inactivating stmn1a, stmn1b, and stmn4l caused brain hemorrhages and hydrocephalus in the brain, similar to that from betaPixfn40a and betaPixm/m mutants (Figure 5C and D, Figure 5—figure supplement 1B–E).