European researchers have identified thirty individuals with a rare form of axonal CMT disease with mutations in the NEFH gene, coding a neurofilament (CMT type 2CC). An analysis of the clinical and laboratory data shows that:
- the first impairments, essentially motor in nature, appear in the patients’ 30s, but progress quickly to a situation of major disability (with loss of ability to walk), unlike the usual forms of CMT;
- muscle deficit is often proximal to begin with, which is not usual in CMT;
- as a result, there is an overlap between the phenotype of CMT 2CC and that of SMN1 gene-related proximal spinal muscular dystrophy.