Genetic and Functional Investigation of Inherited Neuropathies
GENETIC AND FUNCTIONAL INVESTIGATION OF INHERITED NEUROPATHIES Ellen Cottenie MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology Supervisors: Professor Mary M. Reilly, Professor Henry Houlden and Professor Mike Hanna Thesis submitted for the degree of Doctor of Philosophy University College London 2015 1 Declaration I, Ellen Cottenie, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 2 Abstract With the discovery of next generation sequencing techniques the landscape of pathogenic gene discovery has shifted drastically over the last ten years. For the purpose of this thesis, focus was applied on finding genetic causes of inherited neuropathies, mainly Charcot-Marie-Tooth disease, by using both old and new genetic techniques and the accompanying functional investigations to prove the pathogenicity of these variants. Mutations in ATPase 6, the first mitochondrially encoded gene responsible for an isolated neuropathy, were found in five families with CMT2 by a traditional Sanger sequencing approach. The same approach was used to expand the phenotype associated with FIG4 mutations, known as CMT4J. Compound heterozygous mutations were found in a patient with a proximal and asymmetric weakness and rapid deterioration of strength in a single limb, mimicking CIDP. Several appropriate cohorts were screened for mutations in candidate genes with the traditional Sanger sequencing approach; however, no new pathogenic genes were found. In the case of the HINT1 gene, the originally stated frequency of 11% could not be replicated and a founder effect was suggested, underlying the importance of considering the ethnic background of a patient when screening for mutations in neuropathy-related genes.
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