Table 1.

Frequency * of the most common genetically Charcot-Marie-Tooth (CMT) mutations and their clinical associations.

CMT Subtype (Gene Involved)	Inheritance Pattern, Conduction Velocities, Clinical Features	Frequency of Occurrence in Genetically Confirmed CMT Cases
CMT1A (PMP22 duplication)	Autosomal dominant, most common subtype of CMT overall, most common demyelinating form (89% yield with CMT-like phenotype and motor conduction velocities between 15–35 m/s in the upper extremities)	60.5%
CMTX1 (GJB1)	X-linked, intermediate motor conduction velocities, stroke-like episodes or white matter changes, split hand syndrome	16.7%
CMT1B (MPZ)	Autosomal dominant, demyelinating motor conduction velocities, tonic pupils	9.4%
CMT2A (MFN2)	Autosomal dominant, most common form of CMT2, axonal motor conduction velocities, optic atrophy	4.4%

* Frequency distribution adapted from Saporta et al. 2011 [8] (excluding HNPP—hereditary neuropathy with liability to pressure palsies).