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              Printable Handouts
Navigable Slide Index
- Introduction
 - Outline
 - Choroideremia (CHM)
 - X-linked inheritance
 - Absence of male-to-male transmission
 - Clinical manifestations
 - A characteristic phenotype
 - Example 1: 9-year-old CHM male (1)
 - Example 1: 9-year-old CHM male (2)
 - Example 2: 13-year-old case (1)
 - Example 2: 13-year-old case (2)
 - Example 3: 18-year-old case
 - Example 4: 26-year-old case
 - Ring scotoma field tests
 - Visual field vs. visual acuity
 - Female carriers of choroideremia
 - Autofluorescence in female carrier
 - Fundus autofluorecence in a carrier
 - Female carrier with signs in the eye
 - Intrafamilial phenotypic variability
 - Differential diagnosis
 - Choroideremia is different from RP
 - Choroideremia vs. retinitis pigmentosa
 - Choroideremia vs. Usher syndrome
 - Choroideremia vs. gyrate atrophy
 - Refsum disease
 - Choroideremia histopathology
 - CHM phenotype age 30
 - CHM phenotype age 30: histopathology (1)
 - CHM phenotype age 30: histopathology (2)
 - 19-year-old CHM male: macrophage-like cells
 - Polymegathism and hypopigmentation
 - Micrograph of abnormal outer segments
 - Visual electrophysiology and choroideremia
 - ERG in CHM patients
 - Confocal immunolocalization of REP-1 in primates
 - CHM is a defect in cellular trafficking
 - Choroideremia cell biology
 - Cellular effects of a lack of REP-1 (1)
 - Cellular effects of a lack of REP-1 (2)
 - Silencing of CHM gene decreases the colocalization of Rab7A and POS rhodopsin
 - Silencing of CHM gene affects secretion of chemokines but not growth factors by hfRPE cells
 - Summary of cell biology
 - Genetic analysis
 - Genetic analysis of choroideremia
 - Effects of Rab-escort protein mutations
 - Clinical trials and potential therapies (1)
 - Clinical trials and potential therapies (2)
 - CHM AAV2 gene therapy
 - Baseline characteristics of the RPE
 - Optical coherence tomography
 - Serious adverse event: retinal inflammation
 - Pathways of inflammation
 - Fundus autofluorescence area decline
 - Outcome measures: microperimetry
 - Mutant CHM c.1245-521A>G
 - Mutant CHM c.1245-521A>G + AON
 - Antisense oligonucleotide creates full length REP-1
 - Summary of Alberta clinical trial
 - Summary of current clinical trials
 - Thank you for listening
 
Topics Covered
- Introduction to choroideremia
 - Phenotypes and manifestations
 - Inheritance
 - Differential diagnoses
 - Histopathology
 - Cell biology
 - Genetics
 - Clinical trials and potential therapies
 
Talk Citation
MacDonald, I.M. (2022, September 29). Choroideremia: a unique retinopathy [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved November 4, 2025, from https://doi.org/10.69645/EVMW4291.Export Citation (RIS)
Publication History
- Published on September 29, 2022
 
Financial Disclosures
- There are no commercial/financial matters to disclose.
 
A selection of talks on Genetics & Epigenetics
Transcript
Please wait while the transcript is being prepared...
      
      
        
                  0:00
                
                
                  
                    Good day.
                  
                    My name is Ian McDonald,
I'm the Acting Chair
                  
                    of the Department of Ophthalmology
and Visual Sciences
                  
                    at the University of Alberta
in Edmonton, Canada.
                  
                    I'm pleased to speak
with you about
                  
                    choroideremia: a
unique retinopathy.
                  
                
              
                  0:19
                
                
                  
                    Here's the outline of
what I'm going to cover.
                  
                    An introduction,
                  
                    the clinical manifestations
of choroideremia,
                  
                    its differential
diagnosis, histopathology,
                  
                    electrophysiology, some
of the cell biology,
                  
                    the genetic analysis
of choroideremia,
                  
                    and clinical trials and
potential therapies.
                  
                
              
                  0:39
                
                
                  
                    Choroideremia is a
progressive degeneration
                  
                    of the retinal
pigment epithelium,
                  
                    the retina and choroid.
                  
                    Ludwig Mauthner, an
Austrian ophthalmologist,
                  
                    first described
choroideremia in 1872.
                  
                    He believed the
condition represented
                  
                    a congenital absence
of the choroid.
                  
                    Importantly,
                  
                    Mauthner indicated
that choroideremia
                  
                    should be considered
a separate diagnosis
                  
                    from retinitis pigmentosa.
                  
                    Choroideremia is uniquely
a human retinopathy
                  
                    as there are, to my knowledge,
                  
                    no naturally occurring animal
models of this disorder.
                  
                    It is relatively rare,
                  
                    affecting one in
50,000 individuals
                  
                    in a general population,
                  
                    and is present in all
races and ethnicities.
                  
                    Choroideremia is usually
not associated with
                  
                    syndromic features,
                  
                    such as sensorineural
deafness or myopathy.
                  
                    It is an X-linked disorder,
                  
                    and for that reason,
                  
                    a man affected by choroideremia
                  
                    will pass it on to
all his daughters,
                  
                    but none of his sons as they
inherit his Y chromosome.
                  
                    Female carriers of
choroideremia can be
                  
                    identified with distinct
fundus features
                  
                    usually seen by examining
the fundus with
                  
                    imaging techniques that
I will show later.