Due to the haploinsufficiency of PAFAH1B1 and YWHAE in MDS, neuronal migration defects contribute to the “smaller head” phenotype (i.e., microcephaly) observed in these organoids, primarily through the disruption in the cortical niche architecture [75] (Figure 3). The gene discussed is PAFAH1B1; the disease is myelodysplastic syndrome.