X-linked dystonia-parkinsonism (XDP) is a genetic form of dystonia found almost entirely among males of Filipino descent.
Terms used to describe X-linked dystonia-parkinsonism include: XDP, Lubag
XDP is a recessive disorder affecting males almost exclusively. It is characterized by both dystonia and parkinsonism including signs and symptoms such as slow movement (bradykinesia), tremor, rigidity, and a loss of postural reflexes. With disease progression, the dystonia usually becomes generalized. In some patients, signs of parkinsonism may accompany, precede, or "replace" symptoms of dystonia. The disease is transmitted through unaffected females, so-called “carriers.” A few cases have been described in which females who carry a copy of the disease gene may manifest mild symptoms of the disorder, such as relatively mild dystonia or chorea.
XDP is a primarily adult-onset disease starting at age 35 on average with a wide span of onset ranging from late adolescence to the early sixties.
XDP occurs throughout the Philippines but is also diagnosed in the US and Canada in people of Filipino descent. All known cases of XDP originate from one common ancestor. The gene associated with XDP, called the DYT3 gene, was discovered in 2003.
Diagnosis of XDP is based on patient history and neurological examination. Positron emission tomography (PET scans) and olfactory testing may be prescribed.
Treatment for XDP involves using medications to address dystonia, parkinsonism, or both. Parkinsonism symptoms may slightly improve with levodopa or dopamine agonist therapy, and dystonic features may respond to anticholinergics or benzodiazepines such as clonazepam (Klonopin®). Zolpidem and tetrabenazine may be used if dystonia symptoms become multifocal or generalized. Botulinum toxin injections may improve focal dystonias.