X-linked dystonia-parkinsonism or Lubag is a rare genetic form of dystonia found almost entirely among men from the Philippine Island of Panay.
Affecting mainly men, symptoms of X-linked dystonia-parkinsonism can appear as early as age 14. Young-onset patients tend to have focal dystonia that generalises. In these cases parkinsonism may replace dystonia symptoms or may develop with persistent dystonia. Late-onset cases can present with parkinsonian features without dystonia. The parkinsonian features of X-linked dystonia-parkinsonism are similar to those seen in idiopathic Parkinson’s disease with the exception that resting tremor is rarely seen.
X-linked dystonia-parkinsonism was first recognised in the Philippines and among the Panay Island families with the disorder. It is called by the Illonggo name “Lubag.” This name refers to when the twisting movements (dystonia) are intermittent, “wa’eg” when twisting postures are sustained, or “sud-sud” (an onomatopoetic term denoting the sound of sandal slapping the pavement) when the gait is shuffling (a feature of parkinsonism).
Genetic analysis of large Filipino families indicate that the gene locus maps to chromosome Xq13. Pathologic and physiologic studies indicate that this disorder is due to primary degeneration of the striatium with mosaic gliosis. Molecular genetic analysis indicates that the mutation responsible for X-linked dystonia-parkinsonism was introduced into the Olongo ethnic group of Panay more than 2,000 years ago.