Mutations in genes regulating these processes (including STIL and ICQB1 encoding for NPHP5) frequently result in primary microcephaly [205, 206] and ciliopathies [207, 208], respectively, with considerable phenotypic overlap with USP9X patients, thus suggesting that aberrant centrosome duplication and cilia assembly could contribute to MRX99. Here, USP9X is linked to Primary microcephaly.