Centronuclear myopathies (CNM) are a group of congenital myopathies where cell nuclei are abnormally located in the center of muscle cells instead of their normal location at the periphery. Symptoms of CNM include severe hypotonia, hypoxia-requiring breathing assistance, and scaphocephaly. Among centronuclear myopathies, the X-linked myotubular myopathy form typically presents at birth, and is thus considered a congenital myopathy. However, some centronuclear myopathies may present later in life. Presentation
As with other myopathies, the clinical manifestations of MTM/CNM are most notably muscle weakness and associated disabilities. Congenital forms often present with neonatal low muscle tone, severe weakness, delayed developmental milestones (particularly gross motor milestones such as head control, crawling, and walking) and pulmonary complications (presumably due to weakness of the muscles responsible for respiration). Involvement of the facial muscles may cause ophthalmoplegia or ptosis. A mutation in the RYR1 gene causing CNM may also cause susceptibility to malignant hyperthermia, a potentially life-threatening reaction to anesthesia. While some patients with centronuclear myopathies remain ambulatory throughout their adult life, others may never crawl or walk and may require wheelchair use for mobility. There is substantial variability in the degree of functional impairment among the various centronuclear myopathies. Although this condition only affects the voluntary muscles, several children have had cardiac arrest, possibly due to the additional stress placed on the heart.Other observed features have been high arched palate, long digits, bell shaped chest and long face.
IDEA is meant to protect the rights of every disabled student to receive a free and appropriate public education (FAPE) in the least restrictive environment (ideally meaning integrated with non-disabled classmates).Centronuclear myopathies involve pathology at the skeletal muscles, generally without brain involvement or cognitive deficits. Even so, the motor deficits (weakness and associated impairments) may impede in individuals ability to access the educational curriculum (e.g., difficulties lifting or carrying books, difficulties grasping a writing instrument, endurance difficulties throughout the school day, etc.). Further, recurrent respiratory infections may result in missed school days. Terminology
Although all forms of centronuclear myopathy are considered rare, the most commonly known form of CNM is Myotubular Myopathy (MTM). (The terms "centronuclear myopathy" and "myotubular myopathy" are sometimes equated. )Literally, a myopathy is a disease of the muscle tissue itself. Myo derives from the word muscle and pathos means disease. There are dozens of different myopathies, and myopathies are not the only conditions that can cause muscle weakness. Other diseases can cause weakness such as medical conditions affecting sites outside of the muscle itself, including problems in the brain (such as stroke, cerebral palsy, multiple sclerosis), or problems in the spinal cord and/or nerve (such as polio and spinal muscular atrophy). References
External links
GeneReviews/NCBI/NIH/UW entry on X-Linked Myotubular Myopathy or Centronuclear Myopathy