ITPR1 and Ataxia: For example, tough mutated ITPR1 caused GLSP in humans, which typically manifests as craniofacial deformation, aniridia, and ataxia, but aniridia has never been observed in zebrafish, which possess the ITPR1b that is homologous to human ITPR1 and closely related to craniofacial bone formation (23, 28, 32).