Genetic mapping of "Lubag" (X-linked dystonia-parkinsonism) in a filipino kindred to the pericentromeric region of the X chromosome

“Lubag” is an X‐linked disorder causing dystonia and parkinsonism that has only been described in families from the Philippines, Principally from the island of Panay. We have established linkage between the disease phenotype “lubag” and DNA markers which span the Xp11.22‐Xq21.3 region by using a large Filipino family with 8 affected men in three generations. These DNA markers define an interval of about 20 centimorgans in the pericentromeric region of the X chromosome as the most likely site of the disease locus XDPD (X‐linked dystonia‐parkinsonism). XDPD has a maximum multipoint log likelihood ratio score (Zmax) of about 4.6 over the interval from Xq12 to Xq21.31 (DXS159‐DXYS1X). The co‐occurrence of dystonia and parkinsonism in lubag and in other known disorders suggests there may be a common pathogenetic mechanism. Identification of the genetic defect in this family may provide an important clue toward understanding the pathogenesis and pathophysiology of both dystonia and parkinsonism.