Late-onset neuropsychological symptoms in a Japanese patient with megalencephalic leukoencephalopathy with subcortical cysts.

We herein report a Japanese patient with megalencephalic leukoencephalopathy with subcortical cysts (MLC) who developed late-onset neuropsychological symptoms. He demonstrated characteristic clinical features of MLC during childhood, such as slowly progressive megalencepaly, motor impairment with ataxia and spasticity, mild mental retardation, and well-controlled epilepsy. Thereafter, he showed specific neuropsychological symptoms, such as motor and vocal tics, compulsive behavior, perseveration, acquired stuttering, and dystonia since the age of 12. His performance abilities had been unchanged but his verbal abilities had degraded during the past 14 years. Higher cortical dysfunction tests revealed a frontal lobe dysfunction. On repeated brain MRI, a leukoencephalopathy with subcortical cysts remained stationary from infancy. On single photon emission computed tomography (SPECT), a hypoperfusion in the frontal lobe was detected at the age of 3.5 and 17, but the severity of hypoperfusion was also unchanged, respectively. Our results indicate that the frontal lobe dysfunction may be relevant to the late-onset neuropsychological symptoms with MLC.