Known adverse effects of the protein include heterotopic ossification, osteolysis, seroma/hematoma, infections, neurological symptoms (myelopathy, radiculopathy), and retrograde ejaculation.[20] Mulconrey et al[27] reported a subfacial hematoma that required surgical drainage as a postoperative complication in one of 26 patients treated with C.BMP-2. The gene discussed is BMP2; the disease is hematoma.