Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA

Mohamed-Mounir El Mendili (1) , Timothée Lenglet (2) , Tanya Stojkovic (3) , Anthony Behin (3) , Raquel Guimarães-Costa (3) , François Salachas (2) , Vincent Meininger (2) , Gaelle Bruneteau (2) , Nadine Le Forestier (2) , Pascal Laforêt (3) , Stéphane Lehéricy (4, 2) , Habib Benali (1) , Pierre-François Pradat (1, 2)

1 LIB - Laboratoire d'Imagerie Biomédicale [Paris]
2 CHU Pitié-Salpêtrière [AP-HP]
3 Institut de Myologie
4 ICM - Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute

Purpose The mechanisms underlying the topography of motor deficits in spinal muscular atrophy (SMA) remain unknown. We investigated the profile of spinal cord atrophy (SCA) in SMN1-linked SMA, and its correlation with the topography of muscle weakness. Materials and Methods Eighteen SMN1-linked SMA patients type III/V and 18 age/gender-matched healthy volunteers were included. Patients were scored on manual muscle testing and functional scales. Spinal cord was imaged using 3T MRI system. Radial distance (RD) and cord cross-sectional area (CSA) measurements in SMA patients were compared to those in controls and correlated with strength and disability scores. Results CSA measurements revealed a significant cord atrophy gradient mainly located between C3 and C6 vertebral levels with a SCA rate ranging from 5.4% to 23% in SMA patients compared to controls. RD was significantly lower in SMA patients compared to controls in the anterior-posterior direction with a maximum along C4 and C5 vertebral levels (p-values < 10−5). There were no correlations between atrophy measurements, strength and disability scores. Conclusions Spinal cord atrophy in adult SMN1-linked SMA predominates in the segments innervating the proximal muscles. Additional factors such as neuromuscular junction or intrinsic skeletal muscle defects may play a role in more complex mechanisms underlying weakness in these patients.

Domaines: Neurosciences [q-bio.NC]

Mohamed-Mounir El Mendili, Timothée Lenglet, Tanya Stojkovic, Anthony Behin, Raquel Guimarães-Costa, et al.. Cervical Spinal Cord Atrophy Profile in Adult SMN1-Linked SMA. PLoS ONE, 2016, 11 (4), pp.e0152439. ⟨10.1371/journal.pone.0152439⟩. ⟨hal-01304374⟩