CMT4A is caused by autosomal recessive mutations in the GDAP1 gene. Mutations in the GDAP1 gene are associated with causing several types of CMT.
CMT4A symptom onset usually occurs by about 2 years old. CMTers who have CMT4A usually experience a rapidly progressive severe weakening of both proximal and distal muscles. This might lead to an inability to walk and this might also lead to vocal cord paresis and/or vocal cord paralysis.
CMTers who have CMT4A might experience delayed milestones and they will usually experience a fairly severe disease course often becoming wheelchair dependent at an early age.