CMT1C is caused by mutations in the LITAF gene. This gene plays a role in regulating proteins involved in peripheral nerve myelin maintenance. Mutations in the LITAF gene disrupt the normal structure and function of myelin, leading to slowed nerve signal transmission.
CMT1C is autosomal dominant, meaning that just one of the gene’s two copies needs a mutation to cause this subtype.
Clinical Features
Symptoms usually begin in childhood. As with other demyelinating forms of CMT, changes in the peripheral nerves can be detected through nerve conduction studies. Nerve conduction in CMT1C is slowed, reflecting involvement of peripheral nerve myelin.
CMT1C symptoms may include:
- Weakness in the feet and lower legs
- Muscle atrophy
- Foot deformities, including high arches and hammer toes (clawed toes)
- Reduced sensation
- Reduced or absent reflexes
- Enlarged peripheral nerves (hypertrophic nerves)
- Additional symptoms not listed here
Disease Course
CMT1C shows wide variability in severity and progression. Some individuals remain mildly affected, while others develop more severe weakness and functional impairment. Even within the same family, disease severity and progression can differ substantially. Progression is generally slow, and life expectancy is not reduced.
