Charcot-Marie-Tooth disease 4AJoe Segen2016-11-25T07:55:00+00:00
Charcot-Marie-Tooth disease 4A
A severe autosomal recessive demyelinating form (OMIM:214400) of Charcot-Marie-Tooth disease*, which is characterised by early age of onset and rapid progression leading to inability to walk in late childhood or adolescence.
*A disorder of the peripheral nervous system characterised by progressive weakness and atrophy, initially of the peroneal muscles and later of the distal arms. Charcot-Marie-Tooth disease is classified in two main groups on the basis of electrophysiologic properties and histopathology:
• Primary peripheral demyelinating neuropathies (designated CMT1 when they are dominantly inherited) and
• Primary peripheral axonal neuropathies (CMT2). Demyelinating neuropathies are characterised by severely reduced nerve conduction velocities (< 38 m/sec), segmental demyelination and remyelination with onion bulb formations on nerve biopsy, slowly progressive distal muscle atrophy and weakness, absent deep tendon reflexes, and hollow feet. By convention, autosomal recessive forms of demyelinating CMT disease are designated CMT4.
Molecular pathology Defects of GDAP1, which encodes a ganglioside-induced differentiation-associated protein that may play a role in signal transduction during neuronal development, cause Charcot-Marie-Tooth disease—4A.
Synonyms Charcot-Marie-Tooth disease—demyelinating—autosomal recessive, Charcot-Marie-Tooth disease—type 4A Charcot-Marie-Tooth neuropathy—type 4A