Clinical variants of standard CMT2A2 form

27 March 2015

Project Mitofusin 2 is dedicated to people with Charcot-Marie-Tooth type 2A caused by the mutation of Mitofusin 2 protein, both in its standard and in its clinical variants, which are:

HMSN V/CMT V + spasticity in lower limbs (variant including myelopathy)
Autosomal dominant transmission with onset starting from the second decade. Clinical history is consistent with standard CMT2 (weakness in lower limbs) with pyramidal signs (lively osteotendinous reflexes, plantar cutaneous response in extension, with or without spasticity). The clinical status is completed by abnormalities in sensitivity and pain. The disease progression is slow and most patients present with mild disability.

HMSN VI/CMTVI + optic atrophy
Autosomal dominant transmission or sporadic case with onset in childhood years. This variant is often associated with most severe phenotypes and de novo mutations. Clinical history present with a severe motor neuropathy (which is consistent with CMT) and optic atrophy with variable onset (from 5 to 50 years). The optic atrophy is progressive in children and slower in adults, and includes subacute loss of visual acuity with centrocecal scotomata, colour vision impairment and pale disk (which can be detected by an examination of the fundus oculi). In some cases the pathology can improve over time with different levels of regression and partial recovery of the visual acuity (as observed in some cases of Leber’s inherited optic neuropathy).

Recessive axonal neuropathy (AR-CMT2)
This form, with childhood onset, is more severe and has a progressive course leading to deambulation loss. It can present with optic atrophy and scoliosis. Electrophysiological examination shows absence of amplitude and speed reduction in CMAP and SAP with normal NCV.

We would like to invite people who suffer from clinical variants to contact us as well as people who suffer from standard form.