I often get the following question, “Is there any relationship between diabetes and optic nerve atrophy?” This question implies a few different things. So here is my answer.
1. Type 1 Diabetes
I believe that there is no direct relationship between type 1 diabetes and optic atrophy. Type 1 diabetes is an autoimmune disease. Our immune cells attack antigens highly expressed in pancreatic β cells in type 1 diabetes. These autoimmune cells usually do not attack optic nerve although patients with type 1 diabetes are susceptible to other autoimmune diseases. As I mentioned in my previous blog, patients with type 1 diabetes may develop retinopathy if there blood sugar levels are not properly controlled.
2. Wolfram syndrome
In Wolfram syndrome, there is probably a direct relationship between diabetes and optic nerve atrophy. Both pancreatic β cells and optic nerve are susceptible to endoplasmic reticulum dysfunction. So β cell death and death of retinal ganglion cells have the same etiology, i.e. ER dysfunction.
3. Do all patients with Wolfram syndrome have diabetes and optic nerve atrophy?
The answer is, “No.” In most cases, diabetes is the first manifestation of Wolfram syndrome, followed by optic atrophy. However, there are some patients who develop optic atrophy first and don’t develop diabetes for a long period of time. I know one patient with Wolfram whose diabetes was diagnosed at 40 years old. I don’t know why, but it seems like these patients tend to have milder symptoms. I am very interested in carefully studying these patients because I may be able to find a way to delay the progression of Wolfram through these patients. This effort is underway (i.e., modifying my human study protocol).
Image licensed under Creative Commons Attribution 3.0 via Wikimedia Commons
“Three Internal chambers of the Eye” by Artwork by Holly Fischer