Strabismus is a common condition in which the eyes do not align properly, turning inward, outward, upward or downward. Two to four percent of children have some form of it. Some cases can be treated with glasses or eye patching; other cases require eye muscle surgery. But the treatments don’t address the root causes of strabismus, which experts believe is neurologic.

For decades, Elizabeth Engle, MD, in Boston Children’s Hospital’s F.M. Kirby Neurobiology Center, has been studying rare forms of strabismus, such as Duane syndrome, in which strabismus is caused by limited eye movements. Her lab has identified a variety of genes that, when mutated, disrupt the development of cranial nerves that innervate the eye muscles. These genetic findings have led to many insights about motor neurons and how they develop and grow.

More recently, with postdoctoral research fellow Sherin Shabaan, MD, PhD, Engle’s lab has been gathering families with common, non-paralytic strabismus, in which both eyes have a full, normal range of motion yet do not line up properly.

Such “garden variety” forms of strabismus have been much harder to pin down genetically. …