Overactivity is a gain of function in which the mutant protein does more of its normal activity, for example a constitutively active enzyme or an ion channel that stays open, rather than acquiring a new activity or losing function. Adding back wild-type protein does not correct the excess. In CMT, dominant RAB7A alleles cause CMT2B through an overactive GTPase.
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.
