Can Be Homozygous or Can Be Compound Heterozygous
CMT2A2B is caused by autosomal recessive mutations in the MFN2 gene. Autosomal dominant mutations in the same gene are associated with causing CMT2A (CMT2A1, CMT2A2, and CMT2A2A are each the same as CMT2A. Please see the description for CMT2A for a more in-depth explanation of this.).
CMT2A2B symptoms usually start to occur in early childhood, but onset is usually in infancy. CMT2A2B is a particular severe type of CMT. CMTers who have CMT2A2B will usually experience significant foot deformities at an early age, will usually experience significant lower leg atrophy, weakness, mild sensory loss, and might become wheelchair-dependent by early adulthood.
CMTers who have CMT2A2B will usually experience upper limb weakness and atrophy. CMTers who have CMT2A2B might also experience significant kyphoscoliosis (kyphosis is a condition that creates a “hunch back;” scoliosis is a condition in which there is a side-to-side “S” curve of the spine; and the two occurring together is referred to as kyphoscoliosis), optic nerve atrophy, facial weakness, vocal cord palsy and/or vocal cord paralysis, and respiratory muscle weakness.