If it is a pet shop snake, I suspect contagion or disease long before genetic defect.

Pet shop snakes are notorious for having myriad diseases and most are contagious to a high degree.

I am very sorry you lost your baby, something like this is never easy, even if there is nothing you could do about it.

I suggest taking a little time to grieve for her, sterilize everything she came into contact with, and when you are ready, ask here to find a breeder local to you and get yourself a good, healthy baby to love.

Gale