Abstract Details

Title Acute Respiratory Failure Secondary to Myofibrillar Myopathy in a 6-Years-Old

Topic Muscle Disease/Neuromuscular Junction

Presentation(s) P07 - (-)

Poster/Presentation
Number 034

Objective

Background BACKGROUND: Respiratory failure during the first decade of life has been reported but only in the infantile forms of MFM, which were characterized to be caused by recessive deletion mutations in CRYAB resulting in a truncated protein. All subjects died within the first year of life.

Design/Methods DESIGN/METHODS: A retrospective case report.

Results RESULTS: Previously healthy 6-year-old male underwent bilateral adenoidectomy and myringotomy for obstructive sleep apnea secondary to upper airway obstruction. Postoperative course was complicated by persistent respiratory failure and hypercapnia and required multiple extubations and re-intubations and eventual tracheostomy. During the preceding two months patient had also complained of exercise intolerance and fatigue, but there was no associated weakness. Initial examination during the hospital course was unremarkable for any limb weakness; creatine kinase (CK) ranged between 522-1516 iu/L. Motor and sensory nerve conductions were normal. EMG revealed diffuse spontaneous activity in nearly all muscles studied with normal motor unit potentials in right biceps and quadriceps. Testing was limited due to sedation and respiratory decompensation during the study. Muscle biopsy showed marked myofibrillar changes with electron microscopy revealing disintegration of myofibrils at the Z-disk and pleomorphic granulofilamentous material accumulating between myofibrils. Genetic testing showed a novel homozygous missense mutation in exon 2 of the CRYAB gene defined as c.299T>G (p.Val100Gly). Both parents, who are without symptoms, were heterozygous for this mutation. Subsequent examination six months later showed marked axial and spine rigidity; patient continues to be ventilated through a tracheostomy.

Conclusions CONCLUSIONS: MFM presenting with axial and muscle rigidity and respiratory failure can occur with non-truncating homozygous recessive mutations in the CRYAB gene and may present later in childhood.

Authors/Disclosures
Sharon Kim, MD (Kaiser Permanente) PRESENTER	No disclosure on file
Tahseen Mozaffar, MD, FAAN (University of California Irvine)	Dr. Mozaffar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion Pharmaceuticals. Dr. Mozaffar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Argenx. Dr. Mozaffar has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Sanofi-Genzyme. Dr. Mozaffar has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Amicus. Dr. Mozaffar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Grifols. Dr. Mozaffar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Astellas Gene Therapy. Dr. Mozaffar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Bayer. Dr. Mozaffar has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sarepta. Dr. Mozaffar has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Applied Therapeutics. The institution of Dr. Mozaffar has received research support from NIH. The institution of Dr. Mozaffar has received research support from Muscular Dystrophy Association. The institution of Dr. Mozaffar has received research support from Sanofi. The institution of Dr. Mozaffar has received research support from Argenx. The institution of Dr. Mozaffar has received research support from Amicus Therapeutics. The institution of Dr. Mozaffar has received research support from Astellas Gene Therpay. The institution of Dr. Mozaffar has received research support from Cartesian. The institution of Dr. Mozaffar has received research support from Cabaletta. Dr. Mozaffar has received personal compensation in the range of $500-$4,999 for serving as a Study Section Member with NIH.
Maria V. Alvarez, MD (Neurology Assciates)	No disclosure on file

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