Phenotypic overlap in familial and sporadic primary adult-onset extracranial dystonia

Giovanni Defazio, Giovanni Abbruzzese, Paolo Girlanda, Rocco Liguori, Lucio Santoro, Michele Tinazzi, Alfredo Berardelli

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We recently demonstrated that familial and sporadic blepharospasms share several phenotypic features (including age of dystonia onset, sex, and tendency to spread) believed to reflect the etiology of a blepharospasm. To investigate whether familial and sporadic forms of primary adult-onset dystonia other than the blepharospasm also share phenotypic features, we studied the families of 98 probands with primary adult-onset dystonia other than blepharospasms using a validated two-step procedure (questionnaire and clinical examination) that yields 95 % sensitivity and 100 % specificity when used to identify dystonia among relatives. The 98 probands provided a population of 402 living first-degree relatives aged 20 years or more, 336 of whom (83 %, 111 parents, 152 siblings, and 73 children) were screened for dystonia. The screening procedure identified 26 affected relatives (five parents, 16 siblings, and five children; 11 men/15 women; age at dys-tonia onset, 51 ± 11.7 years) from 24/98 families (25 %). No causes of secondary dystonia were found in the relatives who suffered from various forms of dystonia. When familial and sporadic patients were compared, no significant differences emerged in age, education, family size, sex distribution, age at dystonia onset, or tendency to spread. The phenotypic overlap we observed between the study groups suggests that familial and sporadic patients with primary adult-onset dystonia other than blepharospasm probably share a common etiological background.

Original languageEnglish
Pages (from-to)2414-2418
Number of pages5
JournalJournal of Neurology
Issue number11
Publication statusPublished - Nov 2012


  • Adult-onset dystonia
  • Family history of dystonia
  • Genetics
  • Phenotype

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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