This 55YO female has complained of some blurred vision in her left eye for about 6 years. Family history is completely negative for eye disease. Vision was 20/25 in her normal OD and 20/50 OS.
Optos color RG imaging and fundus autofluorescence (FAF) are completely normal for her right eye. The left eye shows severe apparent retinitis pigmentosa (RP) changes that extend from her peripheral macula into the periphery. FAF shows a somewhat scalloped appearance to the preserved central macula with a hyper-FAF ring around the fovea. OCT scanning shows peripheral macular outer retinal and RPE atrophy. Genetic testing was heterozygous for a pathogenic ABCC6 mutation (c.2787+1G>T, splice donor) and a benign ABCA4 variant (c.5603A>T, p.Asn1868lle).
Learning Points:
Unilateral pigmentary retinopathy, also referred to as unilateral RP, is an extremely rare disorder (Alina-Cristina et al, Romanian J Ophth 2016;60:47-52). Patients require long-term follow-up to rule out a delayed bilateral presentation of an inherited retinal disorder (IRD). Unilateral pseudo-RP, chorioretinal findings with intraretinal pigment migration, is much more common, including trauma, prior retinal detachment, and infectious or inflammatory disorders such as AZOOR. The funduscopic and FAF characteristics of our patient’s left eye strongly suggest a unilateral pigmentary retinopathy rather than one of these other imitators.
With our patient’s genetic testing showing two different heterozygous mutations for recessive disorders, her results were essentially negative. However, this does not definitively rule out an IRD. In a real-world study of the Invitae IRD panel, McClard et al yielded a positive diagnostic result in only 51% of patients (J Vitreoretinal Diseases 2022;6:351-357). Each genetic panel has its own limitations regarding which genes are tested, as well as false positives and false negatives (Pulido et al, Retina 2022;42:1-3).
