ITPR1 and aniridia-cerebellar ataxia-intellectual disability syndrome: ITPR1 is also known to localize to structures within the nucleus known as the nucleoplasmic reticulum.42, 43 In the Gillespie syndrome LCLs, the most striking difference compared to control LCLs was a consistently higher proportion of cells that were positive ITPR1 via immunofluorescence (Figure 3B).