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Georgios Kontos, Jennifer Kwan, Robert E MacLaren, Susan Downes; An unusual presentation of choroideremia with macular dystrophy associated with early visual acuity loss. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5387.
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© ARVO (1962-2015); The Authors (2016-present)
Choroideremia is an X-linked recessive retinal degeneration caused by mutations in the CHM gene that encodes Rab escort protein-1 (REP1). Typically, patients present with childhood onset nyctalopia, followed by progressive narrowing of the peripheral visual fields. Central retina, and hence good visual acuity is typically well-preserved until the fifth decade of life. Here we describe an atypical phenotype characterized by profound early central visual loss in a 19-year-old Chinese male, associated with a novel predicted null mutation.
Ophthalmic history, examination, and retinal investigations were undertaken. The entire coding region (exons 1 to 15) including the splice donor and acceptor sites of CHM. were screened.
The patient reported early onset night blindness, significantly reduced central vision as well as bilateral visual field loss. Fundoscopy showed central macular atrophy as well as typical features of choroideremia, with centripetal confluent areas of atrophy in the postequatorial, peripapillary and parapapillary regions. A frameshift mutation c.282delT in exon 4 of CHM was identified and segregation was demonstrated in the family; both his mother and sister were carriers of the same mutation.
We present an unusual macular dystrophy-like presentation of CHM in a young man. He also has a novel c.282delT in exon 4 of CHM which has not previously been reported in patients with choroideremia, but is predicted to be a null mutation. It is likely that other genetic factors may influence the unusual disease course in this case. Choroideremia should be a considered diagnosis in patients with X-linked macular dystrophy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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