title: A rapid immunohistochemical test to distinguish congenital myotonic dystrophy from X-linked myotubular myopathy.
abstract: Severe forms of myotubular myopathy (MTM) and congenital myotonic dystrophy type 1 (CDM), both present as floppy infants with hypotonia, respiratory failure and bulbar insufficiency. Muscle biopsy is often performed as part of the diagnostic process, but these two disorders share very similar histopathological features. It is well documented that CDM muscle has nuclear foci that contain muscleblind-like 1 (MBNL1) protein. In muscle biopsies from eight neonates showing central nuclei, MBNL1 immunolocalisation identified discrete, intensely stained foci in three cases that were subsequently confirmed as CDM by DNA analysis. In the five remaining non-CDM patients and two controls, MBNL1 staining was heterogeneous in nuclei, not as foci. MBNL1 staining patterns in CDM were easily distinguishable from MTM. We suggest that in cases of hypotonia with suspected CDM or MTM, when biopsy has been taken, sections should additionally be stained for MBNL1 to provide a rapid indication of a CDM diagnosis.
authors: Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital NHS Foundation Trust, Oswestry, Shropshire SY10 7AG, UK.
authors: Caroline A
authors: CA
authors: Sewry
authors: Ros C M
authors: RC
authors: Quinlivan
authors: Waney
authors: W
authors: Squier
authors: Glenn E
authors: GE
authors: Morris
authors: Ian
authors: I
authors: Holt
mesh_terms: D000293:Adolescent; D001706:Biopsy / Q000379:methods; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D005260:Female; D005333:Fetus; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D007231:Infant, Newborn; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D020914:Myopathies, Structural, Congenital / Q000175:diagnosis*; D009223:Myotonic Dystrophy / Q000175:diagnosis* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: C493663:MBNL1 protein, human; D016601:RNA-Binding Proteins