This 46YO female was diagnosed with Stargardt disease when she was 17 years old and was referred for genetic testing. Vision was 20/200 OU.
Optos color RG imaging shows bilateral but asymmetric oval hyperpigmented central macular atrophy, greater in OS than OD. Yellow subretinal flecks surround the central atrophy and extend around the nerves and into the midperipheries. On OCT, the central macula shows outer retinal loss with bare Bruch’s membrane, along with patchy loss of the outer retinal bands more eccentrically. On fundus autofluorescence (FAF), the atrophic areas are hypo-FAF, and the flecks are hyper-FAF.
Learning Points:
Stargardt disease is an autosomal recessive disorder caused by a mutation in the ABCA4 gene located on chromosome 1. The ABCA4 transmembrane protein localizes to the photoreceptor outer segments and is involved in the recycling of 11-cis-retinal. Mutations in this gene cause lipofuscin accumulation in the RPE, which eventually leads to photoreceptor and RPE degeneration. Other ABCA4 disorders include fundus flavimaculatus, cone-rod dystrophy, retinitis pigmentosa, and age-related macular degeneration.
Historically, Stargardt disease described patients with macular involvement only, and fundus flavimaculatus described those with flecks extending more peripherally. Both are now considered different retinal phenotypes within the ABCA4 spectrum.
Genetic testing in our patient confirmed two ABCA4 variants in compound heterozygosity, confirming the prior Stargardt clinical diagnosis. Her findings are a bit unusual since these disorders are usually more symmetric between the eyes.