This patient has choroideremia and, luckily, has preserved central 20/30 vision bilaterally. Fundus photography shows patchy areas of RPE and chorioretinal atrophy.
Learning Points:
Choroideremia is an X-linked recessive chorioretinal dystrophy caused by a mutation in the CHM gene. Some female carriers can still develop choroideremia due to irregular inactivation of the X chromosome (lyonization).
Night blindness usually begins between the ages of 10 and 30, followed by peripheral visual field loss. Zones of patchy RPE and chorioretinal atrophy initially appear in the mid-periphery, gradually spreading anteriorly and posteriorly.
Eventually, the patient is left with only a small island of vision, narrowed retinal vessels, and optic atrophy.
