Charcot-Marie-Tooth Disease, Axonal, Type 2h

For a phenotypic description and a discussion of genetic heterogeneity of axonal CMT, see CMT2A1 (118210).

CMT2H maps to the same region that contains the GDAP1 gene (606598), mutations in which cause autosomal recessive demyelinating CMT4A (214400).

Clinical Features

Barhoumi et al. (2001) reported a large Tunisian family with 13 affected patients with autosomal recessive axonal CMT with pyramidal features. Onset was in the first decade, and the disease course was consistent with classic CMT. In addition, patients exhibited a pyramidal syndrome, including brisk upper limb and knee reflexes and brisk Hoffman and palmo-mental reflexes, despite severe muscle wasting.

Mapping

In the Tunisian family with autosomal recessive axonal CMT with pyramidal features, Barhoumi et al. (2001) mapped a locus for the disorder between markers D8S1807 and D8S548. This region overlaps the region of the GDAP1 gene and raised the question of whether mutations in GDAP1 can cause both axonal and demyelinating neuropathic phenotypes (see CMT4A).

Nomenclature

In keeping with the most common designations used in the medical community, 'CMT1' referring to autosomal dominant demyelinating CMT and 'CMT2' referring to axonal CMT, we have chosen to designate this form of autosomal recessive axonal CMT with pyramidal features as 'CMT2H.'