ITPR1 and Ataxia: In this context, it is important to note that parallel loss of IP3R together with two more ataxia-responsible proteins was previously demonstrated in cerebellar tissue of A-T patients [66], namely the calcium homeostasis factor INPP5A (also known as Type I Inositol 1,4,5-Trisphosphate 5-Phosphatase) [220], and CA8 (also known as Carbonic Anhydrase 8) [221,222].