CHOROIDEREMIA presentation dhir hospital bhiwani.pptx

1. CHOROIDEREMIA

2. INTRODUCTION
• X-linked Recessive chorioretinal
dystrophy
• “eremia” meaning barren land :
Almost complete loss of retina, choroid
and RPE that leads to exposure of
sclera
• Diffuse, progressive degeneration of
RPE, photoreceptors and
choriocapillaris.
• Mutation : Chromosome Xq21.2 ,
CHM gene

3. EPIDEMIOLOGY
• 1 in 50,000 to 1 in 100,000 individuals
• M>>F
• Females are carrier
• Finland has the highest reported prevalence
• X inactivation/ Lionization : Carrier females
are usually unaffected , they might develop
nyctalopia in later life

4. PATHOLOGY
• CHM gene encodes for Rab escort protein-1 (REP-
1)
• REP-1 is involved in complex system of
intracellular trafficking of various lipid membrane-
bound structures
• Impaired transport of proteins from the Golgi
apparatus to the outer segments in
photoreceptors, impairment of phagocytosis and
degradation of shed outer segments by RPE cells
• Degeneration : RPE  Photoreceptor layer 
Choroid
• Rods Cones
Note : REP-2 compensates for REP-1 not working in
human body except for eyes

5. SYMPTOMS
• 1st decade: Nyctalopia
• Peripheral vision loss with sparing
of central vision till 5-7 decade
• 5th decade : Visual acuity and colour
vision is lost as degeneration of the
macula takes place

6. FUNDUS EXAMINATION
• Widespread pigment clumping at
the level of the RPE
• Well-defined regions of atrophy with
visible underlying sclera and large
choroidal vessels , advance centrally
• Foveal atrophy occurs in last
• No optic atrophy
• Others : PSC ,macular edema ,
CNVM

7. FLUORESCEIN ANGIOGRAPHY
• Scalloped areas of missing
choriocapillaris appear
hypofluorescent next to
brightly hyperfluorescent
areas of perfused
choriocapillaris
irregular island of hyperfluorescence in the fovea surrounded
by a generalized absence of choriocapillaris, retinal pigmented
epithelium and retina

8. FUNDUS AUTOFLUORESCENCE
• Early loss of peripheral
autofluorescence with subsequent
centripetal loss
• Scalloped edges of demarcation are
sharp
• Hypoautofluorescence in the
nonatrophic areas may precede
photoreceptor cell death Fundus autofluorescence (C) of a patient with choroideremia

9. OCT
• Preservation of the inner retinal layers throughout the disease process
• Progressive subfoveal retinal thinning  visual acuity declines
• Reduced choroidal thickness
• Retinal tubulations in the outer nuclear layers and inner retinal microcysts
• Cystoid macular edema

10. OCTA
• OCTA demonstrated severe
changes in the deep capillary
plexus in both the central
preserved retinal islet and the
surrounding atrophic area and
alterations in the
choriocapillaris in the atrophic
area Superficial and choriocapillaris layers in (a, c) a control male
versus (b, d) the CHM patient
Decreased vascularity in the choriocapillaris layer of the
affected male patient

11. DIFFERENTIAL DIAGNOSIS
• Gyrate atrophy
• Retinitis pigmentosa
• Myopic Degeneration
• Ocular albinism
• Usher syndrome

13. LABORATORY TESTS
• Confirmed by direct genetic testing or through immunoblot analysis with anti-
REP-1 antibody

14. MANAGEMENT
• Investigational Therapies
Gene delivery through the Adeno-Associated Virus Subtype 2 Viral Vector
Retinal prosthesis devices
• Lutein(20mg /day ) : supplement to reduce the progression of atrophy and vision
loss . Works as a filter protecting the macula from blue light and functions as a
free radical scavenger and antioxidant
• Macular Edema : topical dorzolamide , anti-VEGF agents
• Cataract Surgery : phototoxicity from microscope illumination , postoperative
pseudophakic macular edema