Holoprosencephaly as a genetic model for normal craniofacial development

Abstract

Holoprosencephaly is a common developmental defect of the forebrain and midface in humans. Clinical expression is variable, extending in unbroken sequence from a small brain with a single cerebral ventricle and cyclopia to clinically unaffected carriers in familial holoprosencephaly. Significant aetiological heterogeneity in holoprosencephaly has been demonstrated including both genetic and environmental causes. Genetic approaches, such us positional cloning of genes involved in holoprosencephaly will result in a better understanding of normal development of the brain and face and, ultimately, elucidate the basic genetic defects which programme the abnormal formation seen in holoprosencephaly.