The retina is the specialized tissue lining the eye that contains highly specialized cells called photoreceptors. These are the rods and cones that convert light into electrical impulses and send them to the brain for interpretation.
These rods and cones are highly specialized and complex requiring the action of numerous genes for proper formation and function. Consequently, there are numerous mutations that result in vision loss and, in particular, a group of conditions, called retinitis pigmentosa, in which the rods do not function fully and night vision is reduced. Some of these disorders, such as the one described here, have associated signs in the rest of the body.
The first symptom may be night blindness which is noted in the second and third decades of life. The appearance of the retina and optic nerve is characteristic of retinitis pigmentosa with narrowing of the vessels and pigmentary changes. The optic nerve may appear damaged (optic atrophy). Other signs such as obesity and extra digits on the hands and feet may also be present. Speech is sometimes delayed.
This form of retinitis pigmentosa is caused by mutations in a pair of specific genes. The clinically normal parents carry only one copy and there is a 25% chance that both such parents pass their copy of the changed gene to each child in which case the child would inherit this condition.
Retinitis pigmentosa 71 is impossible to diagnose at birth without gene studies. While the extra digits would be apparent, this is a nonspecific sign and, of course, there would be no complaint of night blindness. Later when the difficulty with vision in dim light becomes apparent, a collaborative evaluation with geneticists, pediatricians, and ophthalmologists could suspect the diagnosis.
Nothing is known regarding longevity and there has been no report of treatment.