Charcot Marie Tooth Disease
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		Brief Overview History/Causes Types of CMT Genetics Diagnosis/Prognosis Treatment Living With CMT New Research Interesting Tid-Bits Interview of Child with CMT and Family References
						Types of CMT
			CMT 1 • most frequent (1-2)         • caused by demyelination (1-2)         • three main types listed below (1-2) CMT 1A usually childhood or adolescence (1-2) autosomal dominant (1-2) • caused by a duplication of the PMP22 gene on chromosome 17 (1-2) • accounts for about 60% of all CMT cases (1-2) • causes weakness and atrophy of the lower leg muscles beginning in adolescence and then progress to hand weakness and              sensory loss (1-2) CMT 1B usually childhood or adolescence (1-2) autosomal dominant (1-2) • caused by mutations in the P0 gene (1-2) • usually point mutations which means a mistake in only one letter of the DNA genetic code and researchers have identified over   30 (1-2) • symptom similar to CMT 1A (1-2) CMT 1C usually childhood or adolescence (1-2) autosomal dominant (1-2) • caused by gene defect (1-2) • symptoms similar to CMT 1A (1-2) • not yet been identified (1-2) CMT 2 • less common than CMT 1 (1-2)          • caused by axonopathy (1-2)          • two main types listed below (1-2) CMT 2A usually childhood or adolescence (1-2) autosomal dominantn(1-2) • caused by mutation in 1B-beta protein which codes for the kinesin family member (1-2) CMT 2E usually childhood or adolescence (1-2) autosomal dominant (1-2) • caused by mutation in the neurofilamentlight gene (1-2) CMT 3 infancy (1-2) autosomal dominant, autosomal recessive (1-2) • better known as Dejerine-Sottas disease, rare disorder (1-2) • caused by demyelination (1-2) • severe muscle atrophy, weakness, sensory problems, scoliosis, and ataxia (1-2) • can be caused by mutations that are point specific in the PO or PMP22 gene (1-2) • sometimes looked at as a severe form of CMT 1 (1-2) CMT 4 infancy (1-2) autosomal recessive (1-2) • contains several different subtypes (1-2) • each subtype is caused by a different genetic mutation and have yet to be identified (1-2) • caused by demyelination (1-2) • leg weakness in childhood and by adolescence may not be able to walk (1-2) CMT X childhood or adolescence (1-2) X-linked (1-2) • caused by point mutation in connexin-32 gene on X chromosome (1-2) • often affects males more severely than females (1-2) CHN congenital (at or near birth) (1-2) autosomal recessive, spontaneous (1-2) • associated with hypomyelination, reduced myelin formation, from birth (1-2) • similar to DS although usually has earlier onset and nonprogressive or slow progressive course (1-2) • some children die of respiratory complications during infancy while others grow up and show gradual strength improvements (1-2)
			-There are many different types of CMT and categorized through age of onset, inheritance patter, severity, and whether they are linked to axon or myelin defects.  There are these guidelines but sometimes people fall in-between different types.  For this reason, all of the subtypes are not discussed and detailed here. (1-2) References 1Charcot-Marie-Tooth Disorder Fact Sheet.  National Institute of Neurological Disorders and Stroke.  Available at:  http://www.ninds.nih.gov/disorders/charcot_marie_tooth/detail_charcot_marie_tooth.htm.  Accessed February 15, 2005. 2Facts About Charcot-Marie-Tooth Disease and Dejerine-Sottas Disease.  MDA Publications page.  Available at:  http://www.mdausa.org/publications/fa-cmt.html#types.  Accessed February 15, 2005.