At the age of 50, eight years after the onset of symptoms, following another comprehensive evaluation of the medical history, it became evident that the onset of hyperkinesia had been four years prior to HIV infection; therefore, the patient was tested for HD in a specialized outpatient department for movement disorders, which revealed a positive result with a CAG repeat length of 45 (tolerance +/−1) in the expanded allele of the huntingtin gene (Figure 1B). Here, HTT is linked to movement disorder.