Risk & causes of keratoconus

I had this question for a while and couldn’t find any answers , what are the reasons, risks, and causes of developing keratoconus ?

Is it related to birth ? When does it occur (at which age) ?

I’m asking these questions because my doctor suspected that I have or could develop it since I have a high astigmatism at a young age , after the topography it that I don’t , but I’m still worried about it and I’m seeking info about it risks so I could avoid them.