CMT2O is caused by autosomal dominant mutations in the DYNC1H1 gene. Other mutations within this gene are associated with causing other disorders, but, to date, only one specific mutation within this gene (c.917A>G, p.His306Arg) has been associated with causing CMT2O. The other disorders are not associated with CMT2O.
CMT2O symptom onset usually starts to occur in early childhood, and CMT2O is primarily a motor neuropathy with little to no sensory impairment. Some of the first symptoms are a delay in motor development milestones, and young CMTers who have CMT2O usually will have gait disturbances and difficulty with walking and/or running from an early age.
CMTers who have CMT2O will usually experience a slow progression. Severity can vary, but most who have CMT2O will maintain ambulation throughout their lifetime. Some CMTers who have CMT2O might experience learning difficulties.