Anybody a doctor or works in a hospital etc

So i just got out of the hospital for a collapsed lung (again but they didn't catch the blebs the first go around) and they say i have blebs (or bubbles as i call it) on my lungs I do smoke and they told me the smoking didn't cause this but did contribute I'm 22 been smoking since I was 13 and they are gonna do genetic testing on me june 1st they said I'm too young to have this so my question is what are other way this can happen besides through family and smoking