LAUSR

Background Megalencephalic leukoencephalopathy with subcortical cysts (MLC), or Van der Knaap disease, is a rare spongiform leukodystrophy that is characterized by macrocephaly, progressive motor dysfunction, and mild mental retardation. It is very rare for mental illness such as psychotic disorders, affective disorders and anxiety disorders to occur in MLC. Case presentation A 17-year-old boy was admitted to our hospital after he developed symptoms of depressive state with catatonia after being diagnosed as having MLC with confirmed MLC1 mutation. His catatonic symptoms were improved with administration of olanzapine and sertraline and he was discharged after 4 months. Several months later, he became hypomanic. He was diagnosed with bipolar II disorder. Mood swings were controlled with the administration of carbamazepine. Conclusions This case is the first report of bipolar disorder during the clinical course of MLC. This case indicate the possibility that MLC influences the development of bipolar disorder in MLC, however, further studies involving more patients are required to clarify this.