[Two siblings with adult-type metachromatic leukodystrophy: correlation between clinical symptoms and neuroimaging]

We reported two siblings with adult-type metachromatic leukodystrophy (MLD). Patient 1 was a 19-year-old male, and patient 2 was a 20-year-old female. Their initial symptoms were similar. They developed abnormal behavior and personality changes, poor concentration, and inappropriate smiling. In patient 1, his condition deteriorated and he developed incontinence. His attention span and verbal expression severely decreased. He had an inability to engage in meaningful conversation. The siblings were diagnosed as having MLD by marked reduced leukocyte arylsulfatase A activity. T2-weighted MRI of these two cases showed a high intensity area in the cerebral white matter. The high intensity areas of the cerebral white matter gradually spread over one year. However, SPECT of these cases showed only a few abnormal findings in the initial stage. Using SPECT, a reduction of regional cerebral blood flow (rCBF) spreading to the cerebral cortex was seen over one year after it was seen using MRI. The discrepancy between MRI and SPECT findings in the initial stage was characteristic. MLD is an important disease that involves white matter dementia. The discrepancy between MRI and SPECT is helpful to diagnose white matter dementia.