PPP1R35 (protein phosphatase 1 regulatory subunit 35) is a centrosomal protein essential for centriole elongation and centriole-to-centrosome conversion during cellular division. PPP1R35 localizes to the proximal lumen above the cartwheel within centrioles 1 and functions downstream of the microcephaly protein RTTN by promoting recruitment of microtubule-binding elongation machinery 12. This interaction is critical for proper centriole maturation and centrosome formation 3. Beyond its centrosomal role, PPP1R35 is required for primary cilia assembly and notochord morphogenesis during murine development 4. Clinically, PPP1R35 dysfunction is associated with primary microcephaly (MCPH), a severe neurodevelopmental disorder. A homozygous frameshift indel in PPP1R35 was identified in multiple consanguineous families presenting with severe microcephaly, pachygyria, and global developmental delay 5. Notably, PPP1R35 is phosphorylated by CDKL5, a protein kinase mutated in CDKL5 Deficiency Disorder (CDD), an epileptic encephalopathy affecting children 6. The impaired centriole elongation and cilia morphology resulting from PPP1R35 dysfunction may contribute to neurodevelopmental pathology in CDD.