Abstract
Objective To test for somatic C9orf72 hexanucleotide repeat expansion (HRE) and hexanucleotide repeat length instability in the spinal cord of amyotrophic lateral sclerosis (ALS) cases.
Methods Whole and partial spinal cords of 19 ALS cases were dissected into transversal sections (5 mm thick). The presence of C9orf72 HRE was tested in each independent section using RepeatPrimed PCR and amplicon-size genotyping. Index measures for the testing of mosaicism were obtained through serial dilutions of genomic DNA from an individual carrying a germline C9orf72 HRE in the genomic DNA of an individual without a C9orf72 HRE.
Results None of the sections examined supported the presence of a subpopulation of cells with a C9orf72 HRE. Moreover, the C9orf72 hexanucleotide repeat lengths measured were identical across all the spinal cord sections of each individual patient.
Conclusions We did not observe somatic instability of the C9orf72 HRE in disease relevant tissues of ALS cases.
Glossary
- ALS=
- amyotrophic lateral sclerosis;
- HRE=
- hexanucleotide repeat expansion;
- RPPCR=
- repeat-primed PCR
Footnotes
Funding information and disclosures are provided at the end of the article. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/NG.
The Article Processing Charge was funded by the authors.
- Received October 26, 2018.
- Accepted in final form February 19, 2019.
- Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
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