Genetic and environmental drivers of craniofacial, brain, and pituitary disorders

Congenital pituitary hormone deficiency (CH) is a rare disorder that usually involves deficient production of growth hormone (GH) and other pituitary hormones. Many cases are syndromic, affecting other aspects of craniofacial development and sometimes other organs. There are many genes implicated in congenital pituitary hormone deficiency, and some of them also cause more severe disorders like septo-optic dysplasia (SOD) and holoprosencephaly (HPE). It is not clear why mutations in the same gene can cause such variable clinical features. In addition, the molecular etiology of many cases is not identified with current genetic testing approaches. To realize the promise of the human genome project, more genetic causes need to be identified, and the basis for variable clinical presentations needs to be better understood. In this review we provide information about the overlapping genetic causes of this spectrum of disorders in humans, discuss the influence of genetic background and environment on presentations, and highlight animal models that expand our understanding of how genetic and environmental factors can synergize to generate diverse phenotypes. Evidence for genetic and environmental contributions to this spectrum of disorders is strong.