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Dissection of the Transversus Abdominis Muscle for Whole-mount Neuromuscular Junction Analysis
Published on: January 11, 2014
A Cross-Sectional Study of Nemaline Myopathy
Kimberly Amburgey1, Meryl Acker1, Samia Saeed1
1From the Division of Neurology (K.A.), Genetics and Genome Biology (K.A., M.A., J.J.D., M.B., N.S.), Division of Respiratory Medicine (R.A., F.S., T.T.), Centre for Computational Medicine (M.B., N.S.), Division of Emergency Medicine (M.D.), and Division of Clinical and Metabolic Genetics (S.H.), Hospital for Sick Children; Princess Margaret Hospital (S.S.), Department of Medical Oncology and Hematology; University of Toronto (R.A.), Ontario, Canada; The Manton Center for Orphan Disease Research (A.H.B., C.A.G.), Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, MA; National Institute of Neurological Disorders and Stroke (C.G.B.), Neuromuscular and Neurogenetic Disorders of Childhood Section, and Clinical Research Center (M.S.J.), Rehabilitation Medicine Department, NIH, Bethesda, MD; Department of Computer Science (M.B., M.G., N.S.), University of Toronto, Ontario, Canada; Columbia University Irving Medical Center (A.C.), Division of Pediatric Pulmonology, New York, NY; Goryeb Children's Hospital (J.D.), Department of Pediatric Neurology, Morristown, NJ; Mount Sinai Hospital (C.H.), Prenatal Diagnosis and Medical Genetics, Toronto, Ontario, Canada; Medical College of Wisconsin (M.W.L.), Department of Pathology and Laboratory Medicine, Milwaukee; Children's Hospital of Philadelphia (O.H.M.), Division of Pulmonology, PA; UT Southwestern Medical Center (L.N.), Department of Physical Therapy, Dallas, TX; and Driscoll Children's Hospital (C.H.W.), Division of Neurology, Texas A&M University, Corpus Christi.
Objective:
Nemaline myopathy (NM) is a rare neuromuscular condition with clinical and genetic heterogeneity. To establish disease natural history, we performed a cross-sectional study of NM, complemented by longitudinal assessment and exploration of pilot outcome measures.
Methods:
Fifty-seven individuals with NM were recruited at 2 family workshops, including 16 examined at both time points. Participants were evaluated by clinical history and physical examination. Functional outcome measures included the Motor Function Measure (MFM), pulmonary function tests (PFTs), myometry, goniometry, and bulbar assessments.
Results:
The most common clinical classification was typical congenital (54%), whereas 42% had more severe presentations. Fifty-eight percent of individuals needed mechanical support, with 26% requiring wheelchair, tracheostomy, and feeding tube. The MFM scale was performed in 44 of 57 participants and showed reduced scores in most with little floor/ceiling effect. Of the 27 individuals completing PFTs, abnormal values were observed in 65%. Last, bulbar function was abnormal in all patients examined, as determined with a novel outcome measure. Genotypes included mutations in ACTA1 (18), NEB (20), and TPM2 (2). Seventeen individuals were genetically unresolved. Patients with pathogenic ACTA1 and NEB variants were largely similar in clinical phenotype. Patients without genetic resolution had more severe disease.
Conclusion:
We present a comprehensive cross-sectional study of NM. Our data identify significant disabilities and support a relatively stable disease course. We identify a need for further diagnostic investigation for the genetically unresolved group. MFM, PFTs, and the slurp test were identified as promising outcome measures for future clinical trials.
