Given the appearance of the maculopathy, the possibility of additional ABCA4-retinopathy was considered, particularly homozygosity for c.5882G>A (p.G1961E) [2,3,4,5], a common allele in the Somali population [5]. Subsequently, PCR-amplification and Sanger sequencing of Exon 42 of ABCA4 confirmed homozygosity for this allele. Later, DNA was tested for mutations in a number of genes implicated in macular dystrophies (Stargardt/Macular dystrophy SmartPanel v5; Molecular Vision Laboratory, Hillsboro, Oregon), and the findings were confirmed, with no additional pathogenic mutations identified. Thus, this patient has bi-allelic variants in both ABCC6 and ABCA4, and the phenotype includes features of both, with the maculopathy more likely to be ABCA4-related. Figure 1 depicts FAF imaging when the patient was 31 years old, and also ultra-widefield FAF imaging 9 years later. There has been mild enlargement of the areas of hypo-autofluorescence (both in the central macula and the peripapillary angioid streaks); although, the peripheral retina appears unaffected.

Patients homozygous for this ABCA4 mutation have been reported previously to have limited retinal disease with no peripheral involvement [2,3,4]. Our patient’s ultra-widefield imaging appears to fit with this phenotype, although electrophysiological testing did show evidence of generalised retinal dysfunction as detailed in the first report [1], and the PXE might be contributory. Generalised retinal dysfunction in PXE has been previously reported [6].

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