| Diseases & Conditions -- M |
| Machado-Joseph Disease |
| Macrocephaly, Cutis Marmorata Telangiectatica Congenita Syndrome |
| Macroglossia |
| Macular Degeneration |
| Madelung's Disease |
| Maffucci Syndrome |
| Magnesium |
| Mal de Debarquement |
| Malaria |
| Malignant Hyperthermia |
| Mallory Weiss Syndrome |
| Manic Depression, Bipolar |
| Manic-Depressive Illness |
| Mantle Cell Lymphoma |
| Maple Syrup Urine Disease |
| Marcus Gunn Phenomenon |
| Marden Walker Syndrome |
| Marfan Syndrome |
| Marfan Syndrome |
| Marinesco Sjogren Syndrome |
| Maroteaux Lamy Syndrome |
| Marshall Smith Syndrome |
| Marshall Syndrome |
| Mastocytosis |
| Mastocytosis |
| Maxillofacial Dysostosis |
| Maxillonasal Dysplasia, Binder Type |
| May Hegglin Anomaly |
| McCune Albright Syndrome |
| McKusick Type Metaphyseal Chondrodysplasia |
| Measles |
| Measles |
| Meckel Syndrome |
| Meckel's Diverticulum |
| Meconium Aspiration Syndrome |
| Mediterranean Fever, Familial |
| Medium Chain Acyl CoA Dehydrogenase Deficiency |
| Medullary Cystic Kidney Disease/Nephronophthisis |
| Medullary Sponge Kidney |
| Medulloblastoma |
| Megalocornea Mental Retardation Syndrome |
| Meige Syndrome |
| Melanoma, Malignant |
| MELAS Syndrome |
| Meleda Disease |
| Melkersson Rosenthal Syndrome |
| Melnick Needles Syndrome |
| Melorheostosis |
| Membranoproliferative Glomerulonephritis Type II |
| Men and Women Are Different |
| Menetrier Disease |
| Meniere's Disease |
| Meningioma |
| Meningitis |
| Meningitis |
| Meningitis, Bacterial |
| Meningitis, Meningococcal |
| Meningitis, Tuberculous |
| Meningococcemia |
| Menkes Disease |
| Mental Disorders in Childhood |
| Mental Retardation/Intellectual Disability |
| MERRF Syndrome |
| Mesenchymal Chondrosarcoma |
| Mesenteritis, Retractile |
| Mesothelioma |
| Metabolic Syndrome |
| Metaphyseal Chondrodysplasia, Schmid Type |
| Metatropic Dysplasia I |
| Microvillus Inclusion Disease |
| Middle Ear Infections |
| Mikulicz Syndrome |
| Mild Cognitive Impairment |
| Miller Syndrome |
| Minerals and Electrolytes |
| Mitochondrial Neurogastrointestinal Encephalopathy |
| Mitral Valve Prolapse Syndrome |
| Mixed Connective Tissue Disease (MCTD) |
| Moebius Syndrome |
| Molybdenum |
| Monilethrix |
| Morquio Syndrome |
| Motor Neuron Disease |
| Mountain Sickness, Acute |
| Mowat-Wilson Syndrome |
| Moyamoya Syndrome |
| Mucha Habermann Disease |
| Muckle-Wells Syndrome |
| Mucolipidosis IV |
| Mucopolysaccharidoses |
| Mucopolysaccharidosis Type I |
| Mucopolysaccharidosis Type III |
| Mucous Membrane Pemphigoid |
| Mulibrey Nanism |
| Mullerian Aplasia |
| Multiple Epiphyseal Dysplasia |
| Multiple Sclerosis |
| Multiple Sulfatase Deficiency |
| Multiple System Atrophy |
| Mulvihill Smith Syndrome |
| Mumps |
| Mumps |
| MURCS Association |
| Muscular Dystrophies, Limb Girdle |
| Muscular Dystrophy, Becker |
| Muscular Dystrophy, Duchenne |
| Muscular Dystrophy, Emery Dreifuss |
| Muscular Dystrophy, Oculopharyngeal |
| Mutism, Selective |
| Myasthenia Gravis |
| Mycosis Fungoides |
| Myelodysplastic Syndromes |
| Myeloma, Multiple |
| Myhre Syndrome |
| Myoclonus, General |
| Myopathy, Congenital, Batten Turner Type |
| Myopathy, Desmin Storage |
| Myopathy, Scapuloperoneal |
| Myositis, Inclusion Body |
| Myotonia Congenita |
| Myotubular Myopathy |