RNF43 and Leukoencephalopathy: Downregulated genes included amyloid beta precursor protein‐binding, family a member 2 (APBA2); glycoprotein m6a (GPM6A); megalencephalic leukoencephalopathy with subcortical cysts 1 (MLC1); ankyrin repeat and btb domain containing 2 (ABTB2); and ring finger protein 43 (RNF43).