CMT2D is caused by autosomal dominant mutations in the GARS1 gene. The GARS1 gene is associated with causing several different conditions. However, those mutations are distinct to those conditions, and those conditions are not associated with CMT2D.
CMT2D symptoms usually start between early childhood and a CMTer’s early teens. CMTers who have CMT2D can experience a widely variable set of symptoms and disease course. A CMTer who has CMT2D will usually experience hand weakness and atrophy that is disproportionate to lower leg weakness and atrophy. However, if symptom onset was in early childhood, this characteristic usually will not be the case. Instead, there will be more uniformity.
Some CMTers who have CMT2D might experience significant sensory impairment/loss, while others won’t experience any sensory involvement. Because of this, some CMTers who have CMT2D are thought to have Hereditary Motor Neuropathy Type V, or HMN-V for short (OMIM 600794). HMN-V is an inheritable neuropathy that is purely a motor neuropathy with no sensory involvement. HMN-V is also caused by autosomal dominant mutations in the GARS1 gene. Many consider HMN-V to be a type of CMT, and some CMT clinics treat HMNers.