𝐂𝐡𝐨𝐫𝐨𝐢𝐝𝐞𝐫𝐞𝐦𝐢𝐚
● X linked recessive chorioretinal dystrophy
● Diffuse, progressive degeneration of the RPE, photoreceptors and choriocapillaries
● Mutation in CHM gene codes for REP-1 ( Rab escort protein) , Xq21
𝐏𝐚𝐭𝐡𝐨𝐠𝐞𝐧𝐞𝐬𝐢𝐬
● Primarily degeneration of RPE cells or choroid or both with secondary degeneration of rods and then cones
𝐂𝐥𝐢𝐧𝐢𝐜𝐚𝐥 𝐅𝐞𝐚𝐭𝐮𝐫𝐞𝐬
● Symptomatic during 1st decade of life
● Nyctalopia/night blindness
● Progresses to peripheral vision in teenage years
● Spares central vision until 50-70 years
𝐅𝐮𝐧𝐝𝐮𝐬
● Initial changes begin in midperipheral retina
● Clumping/mottling of pigments at RPE
● Well defined areas of hypopigmentation/atrophy with underlying sclera and large choroidal vessels visible
● Post equatorial region just outside vascular arcades
● Advances centripetally
● Associated with PSC, macular edema, CNV
● Female carriers asymptomatic - fundus can be normal to full blown choroideremia
𝐄𝐥𝐞𝐜𝐭𝐫𝐨𝐫𝐞𝐭𝐢𝐧𝐨𝐠𝐫𝐚𝐦
● Reduced scotopic before photopic
● Reduction in amplitude of full field ERG and delay in b wave implicit time with minimally
increased dark adaptation thresholds
● Extinguished by midlife
𝐓𝐫𝐞𝐚𝐭𝐦𝐞𝐧𝐭
● At present, no treatment
● Macular edema - 2% dorzolamide
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