Description
ClC-2 is a broadly expressed Cl- channel of the CLC family of Cl- channels and transporters which is abundantly expressed in brain. Here it was proposed to participate in lowering the cytoplasmic Cl- concentration of neurons, a process that establishes an inhibitory response to the neurotransmitters GABA and glycine (Staley et al., 1996). Heterozygous mutations in CLCN2 (the gene encoding ClC-2) were recently reported in a few patients with three clinically distinct forms of epilepsy (Haug et al, 2003). However, the disruption of ClC-2 in mice (ClC-2 KO mouse) did not entail epilepsy (Bösl et al., 2001; Nehrke et al., 2002) but myelin vacuolation in fiber tracts of the central nervous system. We used a gene expression profiling of the ClC-2 KO mouse in brain to identify possible disease mechanism which cause the observed myelin phenotype. As these myelin vacuolation became apparent in the fiber tracts of ClC-2 KO cerebellum at P28 and increased with age, we analysed the cerebellum of ClC-2 KO mice at different postnatal ages, before (P14) and after (P35) the KO cerebellum has been affected by myelin vacuolation.