The syndrome of optic nerve hypoplasia (ONH), also known as septo optic dysplasia (SOD) or DeMorsier syndrome, is a congenital disorder characterized by underdevelopment (hypoplasia) of the optic nerves. The optic nerves transmit impulses from the nerve-rich membranes lining the retina of the eye to the brain. Children with ONH may have brain and pituitary malformations. Abnormalities of midline structures of the brain may include absence of the septum pellucidum and hypoplasia of the corpus callosum (nerve fibers that connect the two hemispheres of the brain). The pituitary gland is a hormone-producing gland at the base of the brain that controls hormones in the body that are necessary for growth, energy, and sexual development.Most people with ONH have abnormal eye movements (nystagmus) and vision can range from no light perception to good functional vision, or even full vision in one eye. Some affected children have normal intelligence and others have learning disabilities and developmental delays. Deficiencies of certain hormones may result in growth retardation, poor development, and may be life-threatening without treatment. Hormone deficiencies can be controlled with daily hormone replacement therapy and close monitoring by an endocrinologist (hormone doctor). The cause of ONH is not fully understood.
