Charcot–Marie–Tooths sygdom

Synonymer

CMT, neuropati, Charcot–Marie–Tooth disease, Charcot–Marie–Tooth neuropathy, hereditary motor and sensory neuropathy (HMSN), peroneal muscular atrophy (PMA)

Beskrivelse

Arvelig lidelse der rammer PNS med progressivt tab af muskelvæv og følesans

Forekomst

1:2500

Symptomer

Begynder som regel i den tidlige voksenalder men kan vente til 30-40 års alderen. Første symptom er som regel dropfod.

Årsag

Duplikation af en stor region på den korte arm af kromosom 17 (75% af CMT) som indeholder genet PMP22.

Klassifikation

Clinical categories

Type	Name	Incidence	Notes
CMT1	Demyelinating type	Affects approximately 30% of CMT patients	Causes severe demyelination, thereby impairing nerve conduction velocity.
CMT2	Axonal type	Affects approximately 20–40% of CMT patients	Mainly affects axons. Tends to affect lower extremities more than upper extremities. Clinical symptoms are often less severe than in CMT1. As it is an axonopathy, average nerve conduction velocity is usually not affected (sometimes slightly below normal but mostly above 38 m/s).
CMT3	Dejerine-Sottas disease	Very rare	Does not impair nerve conduction velocity.
CMT4	Spinal type
CMT5	Pyramidal type
CMT6
CMTDI	Dominant intermediate type
CMTRI	Recessive intermediate type
CMTX	X-linked type	Affects approximately 10–20% of CMT patients	This type encompasses all CMT forms that are inherited in an X-linked manner. Average NCV: 25–40 m/s.