It seems to me that a lot of personality disorders are inherited culturally as opposed to biologically.
I read something good today - can't remember where, annoyingly - about how environmental conditions like exposure to germs and toxins, upbringing and wider culture all have an impact on which of our genes express themselves, and how they do so. A gene may or may not manifest a particular physiological trait depending on external factors that the individual is exposed to. So nurture actually has quite a big impact on nature (that the reverse is true is pretty obvious, since a child that's very difficult right from birth will elicit a different response from its parents and other people).
'A lot of personality disorders' is hard to quantify. You might well be right, I mean the classic thing is the violent, alcoholic father who hits his kids because his violent, alcoholic father hit him, and whose kids will likely turn out the same way*. But it's also clear that some disorders really are genetic, since they often manifest in babies that are very difficult right from birth and, as the article mentions, there are some measurable anatomical differences between the brains of people with conditions like psychopathy and normal people.
[*though even in this case, while the violence might be a learned trait it's also well known now that there are important genetic factors in being at risk of alcoholism]
