A Case of Familial Writer's Cramp

Jung, Jae Ik; Choi, Seoung Ho; Cha, Jae Kwan; Kim, Sang Ho; Kim, Jae Woo

Abstract

Writer's cramp is one of the most frequent type of task-related dystonia. It is primarily defined by the appearance of involuntary muscle contractions soon after one begins to write and often co-exists with postural tremor. The cause of writer's cramp as well as other focal dystonia is still a matter of debate. Although the genetic background of some dys-tonia was well known, there have been few cases of writer's cramp that involve other family members. We experienced one family with writer's cramp and postural tremor. A 42-year-old man noted handwriting difficulty of gradual onset which began with postural tremor at the age of 25. When he wrote certain letters or numbers, he automatically had to press hard or hold the pen tightly, experiencing tremor as well as dystonia. His mother and four siblings also had simi-lar disabilities. All were right-handed, and had a postural tremor, prominent in their right hands. They noted the onset of symptoms between the age of 20 and 40. The symptoms had slowly progressed over a period of years and no patient described a remission of symptoms. Two of them eventually no longer attempted to write due to writer's cramp. Two members could write but barely readable and the other two had minimal distress. Alcohol somewhat relieved the cramp in only one of them. Levodopa was no beneficial to the cramp and baclofen relieved the cramp minimally. We report this rare case with familial writer's cramp and postural tremor that suggests autosomal dominant inheritance.