A 76-year-old woman was admitted to our hospital because of transthyretin-related familial amyloid polyneuropathy (TTR-FAP). She had developed bilateral vitreous opacity at the age of 58 and paroxysmal atrial fibrillation at the age of 62. She suffered gait disturbance and dysesthesia of the limbs at the age of 68 and was diagnosed with FAP involving a homozygous Val30Met mutation in the amyloidogenic transthyretin (ATTR) gene after a genetic test. Her parents were cousins, and her aunt's medical history included pacemaker implantation and polyneuropathy. At the age of 74, the patient developed gait disturbance and dysesthesia of her extremities. A neurological examination revealed visual loss, hearing impairment, distal muscle weakness, dysesthesia, and decreased sensation in all modalities in her extremities. She could neither walk nor remain standing without support. Brain magnetic resonance imaging (MRI) revealed a low intensity lesion on the surface of the cerebellum on T2*-weighted images and susceptibility-weighted images. A low intensity pattern that was indicative of the classical type of superficial siderosis was detected. At the age of 76, when she was admitted to our hospital because of the deterioration of her gait disturbance and dysesthesia, brain MRI showed that the patient's cerebellar atrophy and hemosiderin deposition had worsened. Some reports suggest that FAP patients that are homozygous for the ATTR Val30Met mutation are more likely to develop central nervous involvement than those that are heterozygous for the mutation. Superficial siderosis may be responsible for the central nervous involvement.