The 7-dehydrocholesterol reductase (DHCR7) catalyzes the final step of cholesterol biosynthesis;8 mutations in DHCR7 cause cholesterol deficiency and an excess of cholesterol precursors, resulting in craniofacial deformities (e.g., microcephaly, cleft palate, craniosynostosis, and micrognathia), intellectual disability, and behavioral problems in humans.9,10Dhcr7−/− mice show a suckling defect, weight less, immature lungs, distended bladders, and variable craniofacial abnormalities.11 The molecular mechanism of craniofacial anomalies in these conditions is still elusive. The gene discussed is DHCR7; the disease is microcephaly.