Case Report: Guitarist's cramp as the initial manifestation of dopa-responsive dystonia with a novel heterozygous GCH1 mutation

Takafumi Hasegawa, Tatsuhiko Hosaka, Ryuhei Harada, Ichiro Kawahata, Kyoko Hoshino, Naoto Sugeno, Akio Kikuchi, Masashi Aoki

Research output: Contribution to journalArticlepeer-review

Abstract

Dopa-responsive dystonia (DRD), also known as Segawa syndrome, is a phenotypically and genetically heterogeneous group of neurological disorders that typically presents as early-onset lower limb dystonia with diurnal fluctuation, and exhibits a marked, persistent response to levodopa. Heterozygous loss-of-function mutations in the guanosine triphosphate cyclohydrolase 1 (GCH1) are the most common cause of DRD. In addition to the classic form of the disease, there have been a number of studies addressing atypical clinical features of GCH1 related DRD with variable age of onset. This report describes a 37-year-old Japanese male patient with a 10-year history of focal upper limb dystonia that initially emerged as task-specific, guitarist's cramp. The dystonic symptoms responded very well to levodopa treatment, and genetic analysis identified a novel heterozygous mutation in the C-terminal catalytic domain of GCH1. Insufficient recognition of this treatable condition often leads to misdiagnosis, which causes delays in the patient receiving adequate dopamine replenishing therapy. A diagnostic trial with levodopa should be considered in all patients with relatively young-onset dystonia, whether they have classic features of DRD or not.

Original languageEnglish
Article number361
JournalF1000Research
Volume10
DOIs
Publication statusPublished - 2021

Keywords

  • Dopa-responsive
  • Dopamine
  • Dystonia
  • DYT5a
  • GCH1
  • Guitarist's cramp
  • Segawa syndrome
  • Task-specific

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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