X-LINKED
MYOTUBULAR MYOPATHY |
ALTERNATE NAMES
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Myotubular Myopathy; X-Linked Centronuclear Myopathy; Centronuclear Myopathy; Classic
X-Linked Myotubular Myopathy
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DESCRIPTION
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X-Linked Myotubular Myopathy (XLMTM) is a condition that primarily affects muscles used for movement (skeletal
muscles) and occurs almost exclusively in males. Individuals with this condition have
muscle weakness (myopathy) and decreased muscle tone (hypotonia) that is usually evident
at birth. These muscle problems impair the development of motor skills such as sitting,
standing, and walking. Affected infants may also have difficulties with feeding due
to muscle weakness. Individuals with X-linked myotubular myopathy frequently lack
the muscle strength for unassisted breathing and must be supported with a mechanical
ventilator. Some individuals need full-time breathing assistance, while some require
only periodic assisted ventilation, typically during sleep. Affected individuals may
also have weakness in the muscles that control eye movement and other muscles of the
face, absent reflexes, and musculoskeletal deformities or contractures.
Because of their severe breathing problems, individuals with XLMTM usually survive
only into early childhood; however, some people with this condition live into adulthood.
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DIAGNOSTIC TESTING, PHYSICAL FINDINGS,
ICD-9-CM/ICD-10-CM
CODING
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Diagnostic testing: Once clinical manifestations have occurred, the diagnosis is established by a combination
of clinical examination, muscle biopsy, and genetic testing.
Physical findings: The physical findings of XLMTM may include:
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Difficulties with feeding due to muscle weakness;
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Weakness in the eye muscles that control eye movement (ophthalmoplegia);
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Absent reflexes (areflexia);
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An abnormal curvature of the spine (scoliosis);
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Joint contractures of the hips and knees; and
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A large head with a narrow and elongated face.
ICD-9: 359.0
ICD-10: G71.2
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PROGRESSION
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XLMTM presents at birth with weakness, hypotonia, and respiratory distress. Because
of their severe breathing problems, individuals with severe XLMTM usually have a high
incidence of death from respiratory failure in infancy or early childhood. Most males
will fail to reach milestones and will not gain ambulation.
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TREATMENT
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Treatment is supportive and symptomatic. Tracheostomy, G-tube feeding, and assistive
communication devices are often required. Medical subspecialists should address specific
medical complications (for example, scoliosis).
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SUGGESTED PROGRAMMATIC ASSESSMENT*
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Suggested Listings for
Evaluation: |
DETERMINATION
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LISTING
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REMARKS
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Meets |
1.18
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Listing level musculoskeletal findings must be documented; diagnosis of XLMTM or lab
testing results alone does not meet listing severity.
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11.13
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Listing level neurological findings must be documented; diagnosis of XLMTM or lab
testing results alone does not meet listing severity.
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101.18
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Listing level musculoskeletal findings must be documented; diagnosis of XLMTM or lab
testing results alone does not meet listing severity.
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103.02
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Listing level respiratory findings must be documented; diagnosis of XLMTM or lab testing
results alone does not meet listing severity.
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105.10
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111.13
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Listing level neurological findings must be documented; diagnosis of XLMTM or lab
testing results alone does not meet listing severity.
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Equals |
3.02
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3.04
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3.07
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5.07
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* Adjudicators may, at their discretion, use the Medical Evidence of Record or the
listings suggested to evaluate the claim. However, the decision to allow or deny the
claim rests with the adjudicator.
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