Abstract
Abstract: :
Purpose: To describe the clinical and molecular genetic findings of a female carrier of a novel 3'-splice site mutation in intron 6 of the choroideremia (CHM) gene. Methods: A 31-year old woman presented in October 2000 with complaints of difficulties with dark adaptation and a family history of retinal degeneration. Visual acuity measurements, peripheral and color vision tests, electroretinography (ERG), Goldmann visual fields, fluorescein angiogram, CT Scan, and DNA sequence analysis was performed. Results: Dilated fundus examination in October 2000 showed blond fundi with a remarkable granular appearance to the retinal pigment epithelium. No bone spicule pigmentation was observed. The ERG and CT scan were normal. Visual acuity varied between the 20/30 and 20/80 level in the right eye from October 2000 to April 2001, dropping abruptly to 10/200 in mid-April. Acuity remained steady in the left eye at around 20/25. Goldmann visual fields showed the new onset of a central scotoma and enlargement of the blind spot OD. Subretinal hemorrhage was visible under the fovea OD, but definite leakage was not evident on fluorescein angiography. DNA analysis revealed that the patient is heterozygous for a novel mutation at the 3’-splice site of intron 6 of the CHM gene. Final visual acuity in November 2002 was 20/400 OD, and 20/30 OS. Conclusion: A splicing mutation can cause severe visual loss in the carrier state of choroideremia.
Keywords: choroid: neovascularization • retinal degenerations: hereditary • genetics