MLC1 is a 377 amino acid multi-pass membrane protein that may serve as a non-selective neuronal cation channel in brain. Mutant MLC1 proteins that show impaired folding have been corrected in vitro with the addition of a Ca(2+)-ATPase inhibitor, curcumin. Mutations in the gene encoding MLC1 is the cause of megalencephalic leukoencephalopathy with subcortical cysts, also known as van der Knaap disease, a rare syndrome characterized early in life by progressive brain destruction causing mental retardation and incoordination. Single nucleotide polymorphisms within the MLC1 gene may be associated with periodic catatonia, but there seems to be conflicting evidence on whether or not the gene is implicated in general schizophrenia.