Although deletions of the whole CYP26B1 gene have not yet been reported in humans, homozygous point mutations of CYP26B1 were reported in two families, resulting in prenatal and early postnatal lethality, skeletal and craniofacial abnormalities, fusion of long bones, calvarial bone hypoplasia and sutural defects, resulting in craniostenosis and brachycephaly [16]. The gene discussed is CYP26B1; the disease is TWIST1-related craniosynostosis.