Xeroderma pigmentosum group A (XPA) is a hereditary dermatological disease in which hypersensitivity to ultraviolet radiation and various neurological symptoms are observed. In this study, to evaluate the degeneration occurring in the brain of XPA patients, neurological examinations by an established neurologist and 3-Tesla magnetic resonance imaging (MRI) were performed in 10 Japanese XPA patients. MRI studies included diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) in addition to conventional sequences. Neurological examinations revealed various deteriorations in the both central and peripheral nervous systems in all subjects. MRI studies demonstrated age-dependent decline in multimodalities. Severe brain atrophy in conventional sequences, decreased fractional anisotropy (FA) value in DTI, and reduced NAA/Cre ratio in MRS were observed in the adult patients. Multimodal MRI studies unmask the neurological deterioration in XPA patients.