Dominant Intermediate CMT-G is caused by autosomal dominant mutations in the NEFL gene. Mutations in the NEFL gene are associated with causing several types of CMT.
CMTDIG symptom onset usually occurs by the time the CMTer is in their late teens. CMTers who have CMTDIG usually experience slowly progressive lower limb weakness and atrophy that results in gait instability and will usually experience significant hand impairment. More severely affected CMTers who have CMTDIG will usually experience extreme pes cavus, clawed hands, and might even become wheelchair dependent. Some, however, might have a much later symptom onset and have a much milder disease progression.