![Sample our Medicine, Dentistry, Nursing & Allied Health journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5944/TOC-Subject-Sample-2021-Medicine-Dentistry-Nursing-Allied-Health.jpg"})
Abstract
Spinal muscular atrophy and amyotrophic lateral sclerosis are both motor neuron disorders. Several studies have tried to establish a link between the two diseases but the subject is still under debate. In amyotrophic lateral sclerosis, large expansions of the hexanucleotide GGGGCC in intron 1 of the C9orf72 gene are responsible for a variable percentage of familial and sporadic cases. We investigated whether the number of the hexanucleotide repeat in C9orf72 was associated with the phenotype and the number of SMN2 copies in a group of 162 SMA patients. Conventional PCR, repeat primed-PCR and Southern blot were used to determine repeat number and characterize large expansions. Results showed that no pathological (> 30 repeats) or premutated alleles (20–30 repeats) were found. The allelic distribution of the C9orf72 gene in spinal muscular atrophy patients overlapped with the data obtained in our control population, discarding putative repeats that may be associated with the disease. No association was observed with either the SMA phenotype or the number of SMN2 copies. In conclusion, the involvement of C9orf72 as a genetic modifier in spinal muscular atrophy is unlikely. Current investigation of modifier genes in SMA and of the link between ALS and SMA should consider other possible candidates.
Acknowledgements
This work was supported by CIBERER (to LA), GENAME Project (to SB and RMH), and grants FIS 11/2606 and FMM2013 (to EFT). We wish to thank J. Gamez for referring ALS samples for this study, I. Tirado for help in statistic analysis, and O. Dols-Icardo and J. Clarimon for technical help. We also thank the consenting patients and parents who made this study possible.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.