Prior to scientists discovering the first genetic cause of CMT, there were three basic types: CMT1, CMT2, and CMT3. The advent of CMT genetic discovery coupled with a growing understanding of what CMT is has resulted in an ever-evolving manner in which CMT types are classified, categorized, organized, and newly discovered subtypes named. CMT as a disease name has emerged to encompass many different sensory and/motor neuropathies and neuronopathies.
What was three different CMT types thirty years ago has grown into thirteen classifications into which subtypes are organized. Six bear the CMT acronym, seven are represented by non-CMT acronyms, and one group of unclassified subtypes. Unclassified subtypes are known just by their associated gene, such as CMT-DST or CMT-SORD for example.
The thirteen classifications of CMT are CMT1, CMT2, CMT4, CMTX, Dominant Intermediate CMT (CMT-DI or DI-CMT), Recessive Intermediate CMT (CMT-RI or RI-CMT), dHMN, dSMA, GAN, HMSN, HSAN, HSN, SMA-LEP, and one group of unclassified subtypes. Each of these classifications has several subtypes, totaling more than 170 subtypes in all.
