title: The value of respiratory muscle testing in a child with congenital muscular dystrophy.
abstract: Respiratory muscle testing is often limited to noninvasive volitional tests such as vital capacity and maximal static pressures. We report the case of a 12-year-old boy with congenital muscular dystrophy (CMD) in whom invasive and non-volitional respiratory muscle tests showed an elective diaphragmatic dysfunction with the preservation of expiratory muscle strength. This finding, coupled with a clinical phenotype associating diffuse muscle atrophy with finger hyperlaxity and proximal contractures, strengthened the suspicion of Ullrich CMD. Skin-cultured fibroblasts showed intracellular retention of collagen 6 (COL6), muscle magnetic resonance imaging was typical of COL6 myopathy, and molecular studies identified a COL6 gene mutation (COL6A2 c.954+2T>C). The diagnosis of a diaphragmatic dysfunction led to a sleep study that evidenced periods of hypoxemia which justified nocturnal noninvasive ventilation. This case report highlights the benefit of assessing respiratory muscles, through invasive procedure, to assist in clinical diagnosis and to guide clinical management.
authors.affiliation: ASV Santé Gennevilliers, France ; AP-HP, Pediatric Noninvasive Ventilation and Sleep Unit, Hôpital Necker Paris, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Khirani
authors.affiliation: AP-HP, Pediatric Department, Reference Centre for Neuromuscular Disorders (GNMH), Hôpital Raymond Poincaré Garches, France.
authors.forename: Ivana
authors.initials: I
authors.lastname: Dabaj
authors.affiliation: Institute for Maternal and Child Health, Pediatric Department, IRCCS Burlo Garofolo Trieste, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Amaddeo
authors.affiliation: AP-HP, Pediatric Noninvasive Ventilation and Sleep Unit, Hôpital Necker Paris, France ; ADEP Assistance Suresnes, France.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ramirez
authors.affiliation: AP-HP, Pediatric Department, Reference Centre for Neuromuscular Disorders (GNMH), Hôpital Raymond Poincaré Garches, France ; Versailles UVSQ University Versailles, France ; UMRS_974, Inserm Paris, France.
authors.forename: Susana
authors.initials: S
authors.lastname: Quijano-Roy
authors.affiliation: AP-HP, Pediatric Noninvasive Ventilation and Sleep Unit, Hôpital Necker Paris, France ; U 955, Equipe 13, INSERM Créteil, France ; Paris Descartes University Paris, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Fauroux
keywords: COL6-related myopathy; Ullrich congenital muscular dystrophy; diaphragm; respiratory function; vital capacity