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. Author manuscript; available in PMC: 2018 Jan 26.
Published in final edited form as: J Med Genet. 2017 Apr 26;54(6):404–412. doi: 10.1136/jmedgenet-2017-104540

Figure 2.

Figure 2

Summary of phenotypic distinction in patients harbouring the c.5603A>T (p.Asn1868Ile) allele of ABCA4. (A) Patients harbouring biallelic ABCA4 variants, including null alleles, and c.5882G>A (p.Gly1961Glu) report visual symptoms at a mean age of 19.7 and 22.7 years, respectively, while the disease is significantly delayed (to 36.3 years, p<0.0001) in patients with the c.5603A>T (p.Asn1868Ile) allele. (B) The prevalence of foveal sparing is highest among patients with p.Asn1868Ile at 84.7% while observed only in ~33% of cases with other ABCA4 variants including p.Gly1961Glu. (C) Autofluorescence imaging across the macula in a p.Asn1868Ile patient exhibiting foveal sparing within an area of retinal pigment epithelium (RPE) and photoreceptor cell atrophy. (D) A spectral domain-optical coherence tomographic scan across the fovea of the same patient reveals the presence of outer retinal layers: RPE, ellipsoid zone (EZ) and external limiting membrane (ELM) in the fovea. SD-OCT, spectral domain-optical coherence tomography.