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Muscular dystrophy (abbreviated MD) refers to a group of hereditary muscle diseases that weaken the muscles that move the human body.[1][2] Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.[3] Nine diseases including Duchenne, Becker, limb girdle, congenital, facioscapulohumeral, myotonic, oculopharyngeal, distal, and Emery-Dreifuss are always classified as muscular dystrophy[4] but there are more than 100 diseases in total with similarities to muscular dystrophy. Most types of MD are multi-system disorders with manifestations in body systems including the heart, gastrointestinal and nervous systems, endocrine glands, skin, eyes and other organs.[4]
In the 1860s, descriptions of boys who grew progressively weaker, lost the ability to walk, and died at an early age became more prominent in medical journals. In the following decade, French neurologist Guillaume Duchenne gave a comprehensive account of 13 boys with the most common and severe form of the disease (which now carries his name ¡ª Duchenne muscular dystrophy). It soon became evident that the disease had more than one form, and that these diseases affected males of all ages.[citation needed]
These conditions are inherited, and the different muscular dystrophies follow various inheritance patterns. The best-known type, Duchenne muscular dystrophy (DMD), is inherited in an X-linked recessive pattern, meaning that the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes, and is thus considered sex-linked. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must generally be present in both copies of the gene to cause the disorder (relatively rare exceptions, manifesting carriers, do occur due to dosage compensation/X-inactivation). Males are therefore affected by X-linked recessive disorders more often than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Main symptoms include:
• Progressive muscular wasting (weakness)
• Poor balance
• Frequent falls
• Walking difficulty
• Waddling gait
• Calf pain
• Limited range of movement
• Respiratory difficulty
• Drooping eyelids (ptosis)
• Gonadal atrophy
• Scoliosis (curvature of the spine)
• Inability to walk
Few or none of these symptoms may be present before diagnosis. Some types of muscular dystrophy can affect the heart, causing cardiomyopathy or arrhythmias.
Related Information:
Diabetes Muscular dystrophy Spinal Muscular Atrophy Batten disease Ataxia Amyotrophic lateral sclerosis Dementia Multiple system atrophy Parkinson's disease Neuromuscular disease Stroke Multiple sclerosis Brain Injuries Spinal cord disorders Optic neuritis Huntington's disease Schizophrenia disease Major depressive disorder Spasm and convulsions Thyrotoxic Myopathy Polymyositis disease HMSN disease Toxic encephalopathy Autism disease Mental retardation Pachygyria disease SAH Idiopathic intracranial hypertension Mitochondrial myopathies Mitochondrial diseases
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