The iPSC lines derived from ASD patients in these families show decreased cell cycle length, suggesting a generalized increase in proliferative potential. These findings are in accord with earlier hypotheses stating that abnormal control of cell proliferation and overproduction of neurons might explain the accelerated brain growth in ASD (Courchesne et al., 2011; Courchesne et al., 2007; Vaccarino et al., 2009). However, the increased proliferation is seen in early progenitors, but not at later stages of cortical neural development in vitro, suggesting powerful compensatory events that eventually restrict excessive production of neurons in the cortical organoids and presumably also in vivo.
