Different patterns of autofluorescence within the same family in carriers of a novel choroideremia mutation

Abstract

AbstractPurposeChoroideremia (CHM) is a rare retinal dystrophy. It affects both the retina (retinal pigment epithelium (RPE) and outer retina) and the choroidal layers. It is inherited X‐linked and therefore affects all males with a theoretical penetrance of 100%. Female carriers, due to the phenomenon of lionisation may be asymptomatic or suffer from the disease in a similar way to males. On examination, they may have changes in pigment distribution and autofluorescence (AF) changes. They may also have some degree of retinal dysfunction.MethodsWe report a family with two cousins affected by CHM and their carrier mothers. After the diagnosis of an 11‐year‐old male, a complete ophthalmological examination including optical coherence tomography (OCT), microperimetry (MAIA) and AF was performed on all family members. A genetic study was conducted on those cases suggestive of CHM. One other case (a 10‐year‐old cousin) and two carriers, the mothers of the two confirmed cases, were identified. The sisters were not affected.ResultsAll four showed an undescribed mutation in the CHM gene c.1083_1084dupT (p.L362Sfs*56) at location Xp21.2. AF findings were different in both carriers, with a fine speckle pattern on the periphery in one of them and a course and geographic pattern shown low‐density peripapillary pattern and coarse mottled on periphery in the other one. Both affected males showed a clear decrease in the AF pattern with a geographic central persistence (male pattern). During the evolution, one of the patients showed a more aggressive form than the other, which could be justified by the concomitant high myopia in this case. The AF of the carriers remained similar.ConclusionsConsidering that AF is a non‐invasive, fast and accessible test, could serve to diagnose both patients and carriers of CHM. In addition, the pattern of AF in carriers may be different in members of the same family despite having the same mutation.