An 18-year-old female visited a rehabilitation clinic because of weakness of both hands and gait disturbance for >8 years. She showed poor balance and weakness of the whole limb, with the right side more severely involved. In the medical interview, she did not remember the exact starting point of the weakness or any history of trauma. She recalled recognizing the different sizes of her hands at the age of 11 years. After this, her right-hand weakness and gait disturbance progressed. Laboratory examination for systemic disease, routine complete blood count, blood chemistry with electrolytes and muscle enzymes, and autoantibodies revealed no abnormal findings. Other tests such as brain magnetic resonance imaging (MRI) did reveal other hidden diseases or congenital anomalies. Autonomic dysfunction developed, and paresthesia of both hands caused difficulty of activities in daily living. Brain computed tomography did not reveal any abnormality. Plain radiography of the cervical spine revealed the old fracture of the odontoid process (Fig. 1A). MRI of the cervical spine revealed the old fracture of the odontoid process and myelopathy at the C1/C2 levels (Fig. 1B). She underwent spine surgery with “open reduction, C1–2 with temporary lateral mass screw fixation, C1, right”. Thereafter, her neurological progression ceased. Three years after the operation, neurological deterioration did not occur or progress, except for the remaining gait disturbance, autonomic dysfunction, and paresthesia.