CACNA1A loss-of-function affects neurogenesis in human iPSC-derived neural models

: CACNA1A encodes the pore-forming α1A subunit of the CaV2.1 calcium channel, whose altered function is associated with various neurological disorders, including forms of ataxia, epilepsy, and migraine. In this study, we generated isogenic iPSC-derived neural cultures carrying CACNA1A loss-of-function mutations differently affecting CaV2.1 splice isoforms. Morphological, molecular, and functional analyses revealed an essential role of CACNA1A in neurodevelopmental processes. We found that different CACNA1A loss-of-function mutations produce distinct neurodevelopmental deficits. The F1491S mutation, which is located in a constitutive domain of the channel and therefore causes a complete loss-of-function, impaired neural induction at very early stages, as demonstrated by changes in single-cell transcriptomic signatures of neural progenitors, and by defective polarization of neurons. By contrast, cells carrying the Y1854X mutation, which selectively impacts the synaptically-expressed CaV2.1[EFa] isoform, behaved normally in terms of neural induction but showed altered neuronal network composition and lack of synchronized activity. Our findings reveal previously unrecognized roles of CACNA1A in the mechanisms underlying neural induction and neural network dynamics and highlight the differential contribution of the divergent variants CaV2.1[EFa] and CaV2.1[EFb] in the development of human neuronal cells.