PDCD6IP and cerebellar ataxia: Among the genes related to cerebellar volume in the four substructure GWASs we find genes related to ataxia (PEX7, MRPS27, PTK2 [26–28]), neurodevelopment (YPEL3, CASP6, TRIM11, GNB5 [29–32]) and microcephaly (PDCD6IP, USP28 [33, 34]).