Correspondence

Correction

Dystonia

N Engl J Med 2006; 355:1935November 2, 2006

Article

To the Editor:

The review of dystonia by Tarsy and Simon (Aug. 24 issue)1 contains misleading statements about dystonia 3 (also referred to as X-linked dystonia–parkinsonism [XDP] and lubag), which is an important differential diagnosis in people of Filipino descent who present with dystonia, parkinsonism, or both. Table 2 of the article by Tarsy and Simon incorrectly states that dystonia 3 is “endemic in Panay, Philippines.” Although the disorder originated through a founder effect on the Philippine island of Panay, it is not “endemic” there. Rather, XDP occurs in people of Filipino descent independently of their location. Several cases have been diagnosed in the United States, Canada, and Europe. The table also states that there is no known mutation in dystonia 3. In fact, there are several disease-specific sequence changes (DSCs) within the TAF1/DYT3 transcript system, including one in a transcribed exon (DSC3), that facilitate the unequivocal molecular diagnosis of dystonia 3.2

Ulrich Müller, M.D., Ph.D.
Institut für Humangenetik, D-35392 Giessen, Germany

2 References

1. 1

   Tarsy D, Simon DK. Dystonia. N Engl J Med 2006;355:818-829
   Full Text | Web of Science | Medline

2. 2

   Nolte D, Niemann S, Muller U. Specific sequence changes in multiple transcript system DYT3 are associated with X-linked dystonia parkinsonism. Proc Natl Acad Sci U S A 2003;100:10347-10352
   CrossRef | Web of Science | Medline

Author/Editor Response

We thank Müller for pointing out that Table 2 incorrectly lists the mutations for dystonia 3 as unknown. The mutations in the TAF1/DYT3 multiple transcript system should have been listed.1 In the table, the mutation involved in dystonia 8 was also incorrectly listed as unknown, whereas, in fact, mutations have been reported in the myofibrillogenesis regulator 1 (MR-1) gene in association with this disorder.2,3

In their original report, Lee and colleagues described 28 Filipino men with torsion dystonia that was thought to be X-linked, 23 of whom were from the island of Panay.4 A subsequent study confirmed that the prevalence of dystonia 3 in Panay was 13 times that in the general Philippine population. The prevalence in the province of Capiz (which is on the island of Panay) is about 1 case per 4500 men, which is 60 times that in the general population.5 Lee et al. state that “the figures suggest that XDP is endemic in Panay, particularly in Capiz.” We agree with these authors' use of the term “endemic,” meaning a disease usually present or always present in a region or population. Its presence elsewhere does not contradict this designation.

David K. Simon, M.D., Ph.D.
Daniel Tarsy, M.D.
Beth Israel Deaconess Medical Center, Boston, MA 02215
dtarsy@bidmc.harvard.edu

5 References

1. 1

   Nolte D, Niemann S, Muller U. Specific sequence changes in multiple transcript system DYT3 are associated with X-linked dystonia parkinsonism. Proc Natl Acad Sci U S A 2003;100:10347-10352
   CrossRef | Web of Science | Medline

2. 2

   Rainier S, Thomas D, Tokarz D, et al. Myofibrillogenesis regulator 1 gene mutations cause paroxysmal dystonic choreoathetosis. Arch Neurol 2004;61:1025-1029
   CrossRef | Web of Science | Medline

3. 3

   Lee HY, Xu Y, Huang Y, et al. The gene for paroxysmal non-kinesigenic dyskinesia encodes an enzyme in a stress response pathway. Hum Mol Genet 2004;13:3161-3170
   CrossRef | Web of Science | Medline

4. 4

   Lee LV, Pascasio FM, Fuentes FD, Viterbo GH. Torsion dystonia in Panay, Philippines. Adv Neurol 1976;14:137-151
   Medline

5. 5

   Lee LV, Munoz EL, Tan KT, Reyes MT. Sex linked recessive dystonia parkinsonism of Panay, Philippines (XDP). Mol Pathol 2001;54:362-368
   Medline