Science: What is ONH?

Normal vs. small optic discs

Optic nerve hypoplasia, sometimes called septo-optic dysplasia or deMorsier’s syndrome, is the under-development or absence of the optic nerve combined with possible brain and endocrine abnormalities. ONH is the SINGLE leading cause of blindness and visual impairment in children. In some instances ONH includes agenesis (absence) or abnormal development of the corpus callosum and septum pellucidum. These abnormalities can be minor and not cause abnormal brain functions or the brain function can be affected ranging from mild to severe. The areas that can be affected involve gross and fine motor skills; intelligence, speech and interacting with people and in some people these abnormalities cause seizures.

Dr. Borchert with children
Dr. Mark Borchert of Childrens Hospital Los Angeles with Jeremiah, Kambree, Hannah, Jack and Zachary.

The development of the pituitary gland can also be affected by this disorder. The pituitary gland is found at the base of the brain. It is the body’s master control gland; it makes and directs important hormones required for growth, energy control and sexual development. When a person doesn’t make hormones correctly this is called hypopituitarism. The lack of these hormones can cause a great deal of problems for the children who are missing them.

Children need growth hormone to grow normally, control their metabolism, grow and maintain strong bones. The thyroid hormone contributes to the bodies’ ability to grow normally and helps control the bodies’ metabolism (ability to make energy). The pituitary gland also signals the adrenal glands to produce cortisol. Cortisol is needed in times of physical and emotional stress. The pituitary gland produces ACTH, which signals the adrenal gland to produce cortisol in time of stress (such as surgery, illness, dehydration). In addition, you can have problems with development of sex hormones, low blood sugar and if the body is producing too much ADH causing the body to produce too much urine.

All of these endocrine conditions can be managed through daily medication routines. The medications are delivered by nose, mouth or injection. Even with close and careful monitoring of these endocrine deficiencies can be dangerous to those afflicted…without careful monitoring these conditions can be deadly.

[Summarized from Optic Nerve Hypoplasia: A Guide for Parents (PDF), written by Dr. Francine Kaufman, Dr Neal Kaufman, Dr. Mark Borchert and Talia Inlender. Click the link for the full text. En español: Hipoplasia del Nervio Óptico: Guía Para Los Padres (PDF)]