CMTX6 is caused by X-Linked dominant mutations in the PDK3 gene. Because the PDK3 gene lives on the X chromosome, this is an X-Linked CMT.

CMTX6 symptom onset usually occurs by the time the CMTer is 13 years old. A CMTer who has CMTX6 will usually experience lower leg weakness and atrophy causing gait disturbances and foot deformities, and sensory loss in the lower limbs. Weakness and atrophy in the upper limbs primarily causing grip weakness and dexterity impairments in the hands is common with CMTX6. CMTX6 tends to be fairly slowly progressive and the disease severity tends to be milder than its other X-Linked CMT counterparts.

Mild sensorineural hearing loss can be seen with CMTX6. Unlike many of the X-Linked CMT’s, optic involvement nor cerebellar involvement has been reported in CMTX6. The nerve conduction characteristics of CMTX6 are consistent with an axonal CMT.

A trait that sets all X-Linked CMT apart from the other types of CMT is that there can be no male-to-male transmission. Also, males who have X-Linked CMT tend to be more severely affected than females who have X-Linked CMT.