Heterotopias were also detected in a Joubert syndrome patient carrying a mutation in the CELSR2 gene coding for a planar cell polarity protein (Vilboux et al., 2017) essential for neural progenitor cell fate decision, neural migration, axon guidance, and neural maturation (Boutin et al., 2012; Hakanen et al., 2022). The gene discussed is CELSR2; the disease is Joubert syndrome.