The human face: genes, embryological development and dysmorphology.

Clinical dysmorphology is a medical specialty which requires training to systematically observe aberrations in facial development and to understand patterns in the recognition of underlying genetic syndromes. An understanding of normal facial embryology and structure, genetic mechanisms that contribute to facial development and the influence of age, sex, epigenetic, environmental and teratogen effects that contribute to facial dysmorphology are essential. The role of software programmes and databases in achieving diagnoses in subtler phenotypes is growing. A description of specific dysmorphisms of various parts of the human face and key genetic and mechanistic pathways are discussed in this review. Recognizing facial patterns and genetic syndromes efficiently aids in planning appropriate tests, securing an accurate diagnosis, counselling and predicting outcomes and offering interventions and therapies where available.