can a biological child from a good home have RAD?

My younger sister, now in her twenties, has always had problems connecting to my parents. I've been realizing that she has always had most RAD symptoms at least to a mild degree. Controlling, defiant, manipulative, refuses affection, negative attitude, poor self esteem, hyperactive, self-destructive, prefers to be alone, etc. (This is not just a teen thing- she was like this practically from birth). Neither of us were adopted or separated from our parents, we have warm, loving, responsible parents and extended family- absolutely nothing resembling neglect or abuse. She's had a host of different diagnoses, from ADHD to ODD to Asberger's, but nothing really fits. Why would someone have an attachment disorder under these circumstances, or is it even possible?