Studies from our lab in HeLa and Neuro2a cell lines showed that expression of WT Cx47 or the mild HSP related mutant resulted in intercellular puncta consistent with the formation of gap junction plaques, while Cx47 mutations associated with PMLD resulted in intracellular staining colocalizing with Grp94, an ER marker [69] and few (p.M283T) or no (p.P87S and p.Y269D) intercellular plaques. This evidence concerns the gene GJC2 and hereditary spastic paraplegia.