INPP5K and Intellectual disability: Remarkably, the knockdown of INPP5K impaired the outgrowth and the maintenance of dendrite-like protrusions in N2A cells, which may relate to the observation that patients with INPP5K loss-of-function show intellectual disability and brain abnormalities, especially cerebellar or global brain atrophy (Osborn et al., 2017; Wiessner et al., 2017; D'Amico et al., 2020; Hathazi et al., 2021).