The optic nerve connects the eye to the brain and carries visual signals from the retina that enables us to see. Consequently, any disease that damages this nerve can result in vision loss. A number of gene mutations lead to defects of such nerve conduction which may begin with damage to the nerve cells of the retina.
Type 1 optic atrophy can have its onset in early childhood but may not produce symptoms until the second decade of life. The disease is bilateral and often progressive but carriers of the mutation have a wide range of clinical symptoms from none to only hand-motion vision. Likewise, the appearance of the optic nerve may show no damage (in 29% of mutation carriers) to considerable pallor (in 10%) indicative of severe loss of function. Loss of color vision is often noticeable but not all patients have this.
A subset of patients with the mutation also has drooping of the eyelids, unsteadiness, and difficulty moving the eyes in all directions.
This is an autosomal dominant disorder meaning there is a vertical pattern of transmission which usually occurs from parent to child. Affected parents have a 50% chance of each child inheriting the same disorder.
The diagnosis is usually made by an ophthalmologist or sometimes by a neurologist. The prognosis is highly variable but once the optic nerve is damaged, the vision loss is not reversible.