Myotonic Dystrophy

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Myotonic Dystrophy

• By Daniel Medina
• Drew Davis

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Etiology

• Multi-system disorder affecting skeletal muscles,
  heart, eyes, and CNS
• Mutation on chromosome 19
• Three base pair of DNA in 19 repeats are greater
  than 50
• Probability of genetic transmission from parent
  to child is 50
• Clinical severity of disorder worsens through
  mothers side of family
• The care of affected families is coordinated
  through general practitioner, neurologist, and
  clinical geneticist

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Craniofacial Characteristics

• Congenital Myotonic Dystrophy
• Bilateral facial weakness
• Tented upper lip
• Sagging jaw
• Palatal weakness and incompetence
• Myotonia develops in adulthood (temporary muscle
  rigidity)
• Infants have difficulty sucking and swallowing
• As children become older develop inexpressive
  facies
• Talipes

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Craniofacial Characteristics cont

• Adult-onset myotonic dystrophy
• Early adulthood onset
• Ptosis
• Cataracts
• Grip mytonia
• Diabetes

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Medical Diagnosis

• Electromyogram
• Muscle Biopsy
• DNA analysis
• Electrocardiogram

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Clinical Diagnosis

• Weakness in children
• Facial weakness and hypotonia
• monopitch, hoarseness, shorter stretches of
  speech, slow rate, decreased amplitude and
  intelligibility
• Palatal weakness and incompetence (hypernasality)
  
• Tented upper lip and sagging jaw
• Pressure consonants can be affected
  (/b,p,d,t,g,k,z,s,v,f,O,ð,?,?,?,/)

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Treatment

• Speech therapy
• Articulation therapy
• Oral motor exercises strengthening of
  articulators, increase in tone in cheeks
• Myotonia treatment
• Warming up exercise to lessen the effects of
  myotonia on speech production
• A warming-up exercise has been documented in the
  literature as an effective method of overcoming
  myotonia. According to researchers, extensive
  muscle activity can result in a decrease in
  myotonia. In one particular study conducted by
  Swart et. al (2006), warming up with two
  three-minute connected speech samples revealed
  improvement in the number of syllables per second
  and repetition rates in the third three-minute
  connected speech sample. In these patients who
  all presented with at least a mild case of
  flaccid dysarthria, no evidence of muscular
  fatigue was found.

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References

• Amir, A., Wolf, Y., Ezra, Y., Shohat, M., Sher,
  C., Hauben, D.J. (1999). Pharyngeal flap for
  velopharyngeal incompetence in patients with
  myotonic dystrophy. Annals of Plastic Surgery,
  42, 549-552.
• Encyclopedia of Medicine (no date). Myotonic
  Dystrophy. Retrieved September 17, 2006 from
  http//www.Findarticles.com/p/articles/mi_g2601/is
  _0009/ai_2601000942
• Harper, P.S. (2001). Myotonic Dystrophy (3rd
  Ed.). London W.B. Saunders.
• Longman, C. (2005). Myotonic dystrophy. J.R. Coll
  Physicians Edinb, 36, 51-55.
• Muscular Dystrophy News (2005). Myotonic muscular
  dystrophy Another step to another treatment.
  Retrieved October 10, 2006 from
  http//www.medical.newstoday.com/medicalnews.php?n
  ewsid32531
• Penarrocha, M., Bagan, J.V., Vilchez, J.,
  Millian, M.A., Fernandez, S. (1990). Oral
  alterations in Steinerts myotonic dystrophy.
  Journal of Medical Oral Pathology, 69, 698-700.
• Swart, B.J., Engelen, B.G., Kerkhof, J.P.,
  Maassen, B.A. (2004). Myotonia and flaccid
  dysarthria in patients with adult onset myotonic
  dystrophy. Journal of Neurological Psychiatry,
  75, 1480-1482.