Lubag (X-linked dystonia-parkinsonism) has been considered a sex-linked recessive trait and has been mapped to the pericentromeric region of the X chromosome. We studied a 54-year-old man with lubag and two of his female first cousins. Genetic typing was carried out using X chromosome markers. Fluorodopa PET was performed on the man and one of the women. The man had moderately severe parkinsonism and dystonia. A 61-year-old female first cousin had mild left-sided dystonia and her 54-year-old sister had mild generalized chorea. Genetic typing data revealed that all three inherited an X chromosome with marker alleles strongly associated with lubag. Cytologic analysis did not reveal evidence of X chromosomal deletion. Fluorodopa PET in both the man and one affected cousin revealed reduced striatal uptake rate constants consistent with nigrostriatal involvement. These observations suggest that lubag may be a codominant disorder and that it is possible for women to be affected.