Charcot-Marie-Tooth Disease, Neuronal Type

Abstract

CMT2B1 is an axonal peripheral sensorimotor polyneuropathy, with onset in the second decade of life. The disease course is variable, and the disease manifests as distal muscle weakness and atrophy that progress gradually to the proximal muscles and involve the upper and the lower limbs. Sensory impairment may be present, but foot deformities are either moderate or absent. Proximal muscle atrophy of both girdles may occur later in the disease course. The disease is caused by mutations in the LMNA gene, encoding lamin A/C (Table 92.1). Lamins are a major component of the nuclear envelope, separating the nucleoplasm from the rest of the cell. They are composed of an inner and outer nuclear membrane joined at nuclear pores and a nuclear lamina. Lamins A and C are the predominant forms and result from an alternatively spliced protein lamin A/C localized at the nuclear envelope.