Lulu, so sorry to hear about your daughter's issues. But of course you can have the same hope I do. I have often wondered if what my son has (sensory processing/integration disorder) is related to BPD. One seems to be an inability to regulate sensory stimulus (stimuli?), the other an inability to regulate emotional and social stimuli. I notice boys being diagnosed with SPD, girls with BPD. Just a pet theory of mine. I can't help you with the brain science stuff; I would like to learn more too.
I may of been falsely diagnosed the past few years, with the borderline personality disorder as i didnt get it at all when i was a teen (when they say people have it from) but rather got it after my mid 30s after dealing with CFS for 11 yrs or so. None of the BPD specialists took much notice that my previous history didnt really fit with BPD. i personally just think im now weakened on some level so i just cant deal with stressors anymore and it's like something is wrecked now inside of me.. all my ability to emotionally regulate is gone. (i do fit the BPD diagnoses criteria).
i recently got offically the Asperger's diagnoses (at almost 40) and found out if I'd had that previously diagnosed, I may of never ended up with the BPD diagnoses as many of the symptoms are the same eg black and white thinking, explosions to stress, both have trouble dealing with emotions, both self harm eg both BPD and Asperger's people may be cutters or do other forms of self harm etc etc. i've certainly had Asperger's all my life, affecting me all my life. (my father and my youngest daughter.. i think have Autism as there issues in this area are far worst than mine, but they both refuse testing).
Please look into the possibility of Aspergers even if your daughter fits the BPD criteria. .. and yes.. thou so many think BPD is just a personality thing... there has been physiological issues found in studies eg lack of blood flow to certain parts of the brain. (Unfortunately those with BPD are often treated as crap as so many think it's just "a personality disorder" so "you can help it" )
If you want to know anything else about BPD or asperger's let me know. (ive been in therapy for BPD for the past few years.. and this week just started having therapy for the Asperger's).
* Note there is a connection between CFIDS and Autism .. as both have theories out there in which is said can be caused by methylation cycle issues or by toxin triggers (and the XMRV rates is raised in both). (Biting is very common on the Autism spectrum, my daughter used to bite people a lot)