CACNA1A and Parkinson disease: In the past decade, neuronal cells derived from patient-specific iPSCs have been generated to model neurodegenerative diseases such as PD [32, 33], Alzheimer's disease (AD) [34, 35], and HD [36, 37], and relatively handful iPSC studies focused on cerebellar ataxias including Friedreich's ataxia (FRDA) [38–43] and SCAs: SCA2 [44], SCA3 [45–48], SCA6 [49], SCA7 [50], SCA14 [51], and SCA36 [52].