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Neurodegeneration
Research paper
Widespread structural brain involvement in ALS is not limited to the C9orf72 repeat expansion
  1. Henk-Jan Westeneng1,
  2. Renée Walhout1,
  3. Milou Straathof2,
  4. Ruben Schmidt1,
  5. Jeroen Hendrikse3,
  6. Jan H Veldink1,
  7. Martijn P van den Heuvel4,
  8. Leonard H van den Berg1
  1. 1Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
  2. 2Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
  3. 3Department of Radiology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
  4. 4Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
  1. Correspondence to Professor Leonard H van den Berg, Department of Neurology, G03.228, University Medical Center Utrecht, P.O. Box 85500, Utrecht 3508 GA, The Netherlands; L.H.vandenBerg{at}umcutrecht.nl

Abstract

Background In patients with a C9orf72 repeat expansion (C9+), a neuroimaging phenotype with widespread structural cerebral changes has been found. We aimed to investigate the specificity of this neuroimaging phenotype in patients with amyotrophic lateral sclerosis (ALS).

Methods 156 C9− and 14 C9+ patients with ALS underwent high-resolution T1-weighted MRI; a subset (n=126) underwent diffusion-weighted imaging. Cortical thickness, subcortical volumes and white matter integrity were compared between C9+ and C9− patients. Using elastic net logistic regression, a model defining the neuroimaging phenotype of C9+ was determined and applied to C9− patients with ALS.

Results C9+ patients showed cortical thinning outside the precentral gyrus, extending to the bilateral pars opercularis, fusiform, lingual, isthmus-cingulate and superior parietal cortex, and smaller volumes of the right hippocampus and bilateral thalamus, and reduced white matter integrity of the inferior and superior longitudinal fasciculus compared with C9− patients (p<0.05). Among 128 C9− patients, we detected a subgroup of 27 (21%) with a neuroimaging phenotype congruent to C9+ patients, while 101 (79%) C9− patients showed cortical thinning restricted to the primary motor cortex. C9− patients with a ‘C9+’ neuroimaging phenotype had lower performance on the frontal assessment battery, compared with other C9− patients with ALS (p=0.004).

Conclusions This study shows that widespread structural brain involvement is not limited to C9+ patients, but also presents in a subgroup of C9− patients with ALS and relates to cognitive deficits. Our neuroimaging findings reveal an intermediate phenotype that may provide insight into the complex relationship between genetic factors and clinical characteristics.

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

https://doi.org/10.1136/jnnp-2016-313959

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    Footnotes

    • H-JW and RW contributed equally.

    • Contributors H-JW, RW, MS, MPvdH, JHV and LHvdB contributed to the study concept and design. H-JW, RW, RS, EV and JH participated in data collection and processing. H-JW, RW, MS, RS, JHV, MPvdH and LHvdB contributed to the analysis and interpretation of data. H-JW, RW and MS wrote the manuscript. RS, JHV, MPvdH and LHvdB revised the manuscript for important intellectual content. LHvdB and MPvdH provided study supervision and obtained funding.

    • Funding This study was supported by the ALS Foundation Netherlands, the European Community's Health Seventh Framework Programme (grant agreement n° 259867), and The Netherlands Organization for Health Research and Development: SOPHIA project (funded through the EU Joint Programme—Neurodegenerative Disease Research, JPND).

    • Competing interests LHvdB reports grants from ALS Foundation Netherlands, grants from The Netherlands Organization for Health Research and Development (Vici scheme), grants from The European Community's Health Seventh Framework Programme (grant agreement n° 259867 (EuroMOTOR)), and grants from The Netherlands Organization for Health Research and Development: SOPHIA, funded through the EU Joint Programme—Neurodegenerative Disease Research, JPND, during the conduct of the study; personal fees from Biogen, personal fees from Cytokinetics, grants and personal fees from Baxalta outside the submitted work.

    • Patient consent Obtained.

    • Ethics approval Medical Ethical Committee of the University Medical Center Utrecht.

    • Provenance and peer review Not commissioned; externally peer reviewed.