CMT2E is caused by autosomal dominant mutations in the NEFL gene. Other autosomal dominant mutations in this gene cause Dominant Intermediate CMT and the demyelinating CMT1F. CMT2E is sometimes expressed as CMT1F/2E or CMT2E/1F, depending on author.
CMT2E is an axonal CMT, meaning that the peripheral nerve axon is primarily affected by the CMT. CMT1F, also caused by autosomal dominant mutations in this gene is a demyelinating type of CMT, meaning the peripheral nerve myelin is primarily affected by the CMT.
CMT2E symptoms usually start to occur in the CMTer’s teens and 20s. CMTers who have CMT2E usually will experience lower leg weakness and atrophy that leads to pes cavus (high arches), hammertoes, and ankle instability/weakness. The intrinsic muscles of the hand can become weakened and atrophied, resulting in loss of dexterity and contractures (clawed hands).
CMT2E severity, symptoms, progression (albeit usually slow), and age at onset can be widely variable, and even within the same family.