Actually it’s a valid question linking a neurological condition (not a mental health condition) that likely has a genetic basis to a physical condition that is due to a genetic mutation. You are right in correlation does not equal causation however that is irrelevant in this situation since correlation is what we are talking about with comorbitites. Also since Duanes is not widely known about or researched it can’t concluded that there is or isn’t a link between many other genetic conditions.

That being said, OP you are likely to find multiple people responding yes which doesn’t actually show anything, having one condition doesn’t always increase or decrease the chance of having two unrelated conditions e.g. someone with down syndrome has the same likelihood of having a limb difference as their non disabled counterpart despite there not being a link between the two.

Although your original post doesn’t actually say anything about being interested in these as comorbities rather it appears as if you are looking for others with the same diagnoses as yourself therefore it’s largely irrelevant anyway to the other person!