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To help improve BCD awareness, ERN-Eye (European Reference Network dedicated to rare eye diseases) distributed BCD info to all of its centres last week. Step by step, with help and support from organisations such as ERN-Eye, we hope more and more eye doctors will become aware of BCD. This will ensure a higher percentage of BCD patients to get correctly diagnosed.
To put the BCD misdiagnosis problem into context, several factors to consider.
1. There are more than 200 genes whose mutations can cause blindness. Many retinal degenerative diseases share similar phenotypes. Therefore, it is difficult to correctly diagnose an inherited retinal disease based on clinical symptoms and phenotypes alone. The following paper is a good example of this problem. Patients in this study suffer from various retinal diseases (including BCD which was referenced as CYP4V2 in the paper) but were correctly diagnosed only after next-generation sequencing. Patients were recruited from some key eye centers in the U.S., Canada and the UK.
Next generation sequencing-based molecular diagnosis of retinitis pigmentosa: identification of a novel genotype-phenotype correlation and clinical refinements. (2014) Hum Genet;133(3):331–345.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945441/2. Among retinal diseases, BCD are often misdiagnosed due to:
– Crystals in the retina is not unique to BCD. There are other types of crystalline retinopathies which also have crystals in the retina.
– Crystal deposits may not be obvious in some early- or late-stage BCD patients.
Hence, BCD is often diagnosed as Retinitis Pigmentosa (RP) in general, or as Stargardt’s disease, choroideremia or other retinal degenerative diseases, or sometimes even totally missed.Researchers suggested infrared imaging can help improve BCD clinical diagnosis. Genetic testing of CYP4V2 mutations is the ultimate tool to confirm BCD diagnosis. For more info on BCD misdisangosis, see https://www.invinciblevision.org/bcd-and-misdiagnosis/misdiagnosis-and-underdiagnosis/
The_35th_owl: Sounds like that your case is another paediatric case of BCD given when you noticed the first symptoms. There has been published reports of BCD paediatric cases. See “BCD Paediatric Cases” of this forum.
Interesting that you mentioned you started seeing retinal specialists from the age of 10. For most BCD patients, first noticeable symptoms begin in 20s or 30s. But there are BCD patients whose disease onset is earlier. My elder sister experienced night blindness when she was a teenager. There are case reports of paediatric patients. I will start a topic on BCD paediatric cases and include the published case reports there.
I wish that year 2020 will bring hope closer to the BCD community so that one day many BCD patients do not have to go through the same pain and suffering that my sister and I have gone through.
Yes, photophobic is a very annoying symptom. Often I had to explain to people why I wore sunglasses when the light is not strong (to normal people). Otherwise, people think you are a weirdo or better yet, a celebrity:)
My first BCD symptom began with night blindness in very dark environment when I was in my 20s. As time goes by, I have experienced blind spots in my visual fields. Meanwhile, my visual acuity and contrast sensitivity dropped. One thing I was very nervous about was walking the stairs because I could not see the edges of the stairs well, particularly when I walked down stairs. At the early phase of BCD, I was still able to do what a normal sighted person can do.
Then as my vision continued to deteriorate, I could no longer read small font size on paper, and reading on normal white background computer screen became an exhausting task for me because my eyes because very sensitive to strong light. What I meant by strong light is not just outdoor strong sunlight, but also indoor light that is totally fine for people with normal vision. Then I had to use invert color function on computer and phone to read, together with the zoom function.
After I turned 40, BCD disease progression went faster. Color vision impaired, visual acuity dropped very fast, and blind spots became bigger and distorted vision also became more obvious. I had to rely on VoiceOver to read because my eyes cannot read on computer screen for more than a few minutes (even with invert color and large zoom). I started to walk with a cane or my guide dog to cope with the changes in life.