Detailed Analysis of ITPR1 Missense Variants Guides Diagnostics and Therapeutic Design.

Background: The ITPR1 gene encodes the inositol 1,4,5-trisphosphate (IP ) receptor type 1 (IP R1), a critical player in cerebellar intracellular calcium signaling. Pathogenic missense variants in ITPR1 cause congenital spinocerebellar ataxia type 29 (SCA29), Gillespie syndrome (GLSP), and severe pontine/cerebellar hypoplasia. The pathophysiological basis of the different phenotypes is poorly understood.