CLCN2 and cerebellar ataxia: CLCN2-related leukoencephalopathy (CC2L), also known as leukoencephalopathy with ataxia (LKPAT; MIM #615651), is a rare autosomal recessive disorder caused by mutations in the CLCN2 gene (600570) on chromosome 3q27.1, causing the dysfunction of its encoded ClC-2 chloride channel protein, which is characterized by intramyelinic edema [1–3].