An interchromosomal insertion, also called an insertion translocation, is a structural variant in which a segment of one chromosome is inserted into a different chromosome, rather than a base being changed in place within a gene. In Charcot-Marie-Tooth disease (CMT), CMTX3 is caused by this kind of variant: a segment from another chromosome (classically chromosome 8) inserted into a palindrome region at Xq27.1, a non-coding structural change now linked to altered regulation of the nearby SOX3 gene rather than to a coding mutation. This is why CMTX3 is listed as a translocation variant rather than a single-gene (monogenic) cause.
A Name That Does Too Much Work
Jean-Martin Charcot's name appears throughout medicine, but nowhere does it create more confusion than in the foot. Learn why the CMT foot and Charcot neuroarthropathy, also known as Charcot foot, share a name yet differ in how they develop, appear, and are managed.
