I'm very sorry to hear about your daughter. You're definitely talking about a problem that needs a haematologist here.
I can't help with diagnostic suggestions I''m afraid (I'm a paediatrician specialising in disability), but my first question would be "which hospital is she attending?" If she's got something incredibly rare that a specialist children's hospital can't identify, then you should seriously think about asking for a second opinion from Great Ormond Street. If she's already under GOSH, then you've already got the best paediatricians in the country working on it.
Please pm me if you wish.