Clinical Trials Involving Rare Diseases: O
- Occipital Horn Syndrome (2)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Melanoma (64)
- Ocular Muscular Dystrophy (7)
- Ocular Toxoplasmosis (4)
- Oculo-auriculo-vertebral Spectrum (10)
- Oculocerebral Syndrome With Hypopigmentation (5,062)
- Oculocutaneous Albinism (14)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontoma (1)
- Ogilvie Syndrome (3)
- Olfactory Neuroblastoma (66)
- Oligoastrocytoma (99)
- Oligodendroglioma (391)
- Olivopontocerebellar Atrophy (3)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (28)
- Oncogenic Osteomalacia (14)
- Opisthorchiasis (1)
- Opsoclonus-myoclonus Syndrome (6)
- Optic Atrophy 1 (5)
- Optic Neuritis (166)
- Optic Pathway Glioma (43)
- Oral Cancer (543)
- Oral Leukoplakia (33)
- Oral Squamous Cell Carcinoma (189)
- Oral Submucous Fibrosis (10)
- Orbital Lymphoma (2)
- Organic Acidemias (16)
- Ornithine Transcarbamylase Deficiency (30)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Orotic Aciduria Type 1 (1)
- Osteochondritis Dissecans (27)
- Osteochondroma (28)
- Osteochondrosis (34)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (65)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (11)
- Osteogenesis Imperfecta Type IV (2)
- Osteogenesis Imperfecta Type VI (5)
- Osteomalacia (47)
- Osteomyelitis (105)
- Osteopetrosis (20)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteosarcoma (622)
- Ostium Secundum Atrial Septal Defect (7)
- Oto-Palatal-digital Syndrome (2)
- Oto-palato-digital Syndrome Type 1 (2)
- Ovarian Cancer (3,151)
- Ovarian Carcinosarcoma (32)
- Ovarian Epithelial Cancer (2,941)
- Ovarian Germ Cell Tumor (186)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (4)