Eye floaters are small moving spots in our vision. They are noticeable when we look at something bright, such as blue sky or white paper. I think eye floaters are not caused by gene. Most of us will suffer from eye floaters in our life. They are really annoying but they are harmless if you just got a few of them. Many people choose to ignore them.
Eye floater is not genetic. If you just have little eye floaters they may improve over months to years. But as to your mum, I think it can be a sign of a more serious condition. Retinal detachments are a kind of very serious disease. But I don't mean that eye floaters will cause the retinal detachment. It is just a sign of a retinal detachment. I suggest you to see eye doctors with your mum.