Members of my research laboratory combine clinical, genetic, and molecular biologic approaches to the study of congenital strabismus. Strabismus, which is misalignment of the eyes, affects 2-4% of the population and causes loss of binocular vision and amblyopia (vision loss in a structurally normal eye). The cause of strabismus when it occurs in the absence of structural brain abnormalities is generally unknown. In the last decade, we have focused our research studies on understanding the genetic etiology of a series of complex strabismus syndromes in which eye movement in at least one direction is limited or paralyzed. We are discovering that these disorders result from mutations in genes necessary for the normal development and connectivity of brainstem ocular motoneurons, including PHOX2A, SALL4, KIF21A, ROBO3, and HOXA1, and we now refer to these syndromes as the "congenital cranial dysinnervation disorders," or CCDD.