Cellularity Defects Are Not Ubiquitous in the Brains of Fetuses With Down Syndrome

This neuroanatomical study examined brain cellularity in fetuses with Down syndrome (18-22 weeks gestation) across multiple regions, finding significant cell reduction in basal ganglia structures (putamen -30%, globus pallidus -35%) but normal cell counts in insular and cingulate cortex. The selective hypocellularity pattern suggests motor abnormalities in Down syndrome may relate to basal ganglia defects rather than ubiquitous brain underdevelopment.