TN 15 (09-17)
DI 23022.143 Congenital Myotonic Dystrophy
CONGENITAL MYOTONIC DYSTROPHY
Myotonic dystrophy is a rare, inherited neurological disorder caused by a mutation of the DMPK gene. The disease is characterized by the repeating CTG nucleotide bases in DNA. Congenital Myotonic Dystrophy (type 1) is the most severe form, with signs and symptoms apparent after birth. These can include severe muscle weakness resulting in respiratory insufficiency, dysphagia leading to aspiration pneumonia, cardiomyopathy, and failure to thrive. Developmental delays are common. Later complications may include excessive daytime sleepiness, intellectual disability, autism, and ADHD. If the child survives to adulthood, he/she will start to take on the symptoms commonly seen in adult myotonic dystrophy type 1 as well.
DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Diagnostic testing: Congenital myotonic dystrophy is difficult to recognize because there can be multiple causes of weakness and hypotonia in newborns. The diagnosis can be confirmed through molecular genetic testing. Other means of diagnosis are electromyography (EMG), muscle biopsy, and sometimes-elevated serum CK concentration.
Physical findings: Physical examination shows general muscle weakness, especially of the face and throat muscles, dyspnea, dysphagia, ineffective nursing due to weak suck, slurred speech, extremity contractures, and developmental delays.
ICD 9: 395.21
ONSET AND PROGRESSION
For congenital myotonic dystrophy, abnormal muscle weakness and other findings are present at birth. Progression occurs throughout the child’s lifetime; however, the rate and severity may vary, even with family members.
Currently there is no cure for this disorder. Treatment is supportive and symptomatic.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for evaluation:
Suggested Listings for Evaluation:
Listing-level severity must be documented.
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* Adjudicators may, at their discretion, use the Medical Evidence of Record or Listings suggested to evaluate the claim. However, the decision to allow or deny the claim rests with the adjudicator.