title: Sex differences in clinical and genetic determinants of levodopa peak-dose dyskinesias in Parkinson disease: an exploratory study.
abstract: BACKGROUND
  Several factors, both clinical and genetic, may account for the risk of developing levodopa-induced peak-dose dyskinesias (PDD) in patients with Parkinson disease, but it is unclear how these factors interact for modulating the individual susceptibility for PDD.
  
  
  OBJECTIVE
  To examine clinical and genetic risk factors for determining individual susceptibility of PDD in patients with Parkinson disease.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Referral center for Parkinson disease in Calabria, southern Italy. Patients Two hundred fifty patients with Parkinson disease were screened for the presence or absence of PDD following a short-term levodopa administration, and 215 subjects were available for further evaluations, including genotypic analysis of the CA dinucleotide short tandem repeat (CAn-STR) polymorphism located in the dopamine receptor D2 gene (DRD2).
  
  
  RESULTS
  One hundred five patients (48.8%) exhibited PDD following short-term levodopa administration, and 110 patients (51.2%) did not. Multivariate logistic regression analysis showed that independent predictors for the occurrence of PDD were female sex, earlier age at onset of Parkinson disease, longer duration of treatment, and higher dose of levodopa. Genetic factors related to the DRD2 CAn-STR polymorphism were not independent predictors for PDD in the total population, but they had a strong protective effect on the appearance of PDD when the multivariate analysis was performed in men (odds ratio, 0.34 [95% confidence interval, 0.14-0.84]). In women, a genetic protective effect on PDD was not evident.
  
  
  CONCLUSIONS
  Risk factors for PDD, both clinical and genetic, act in different ways for men and women. Genetic factors related to the DRD2 polymorphic status have a protective effect on PDD development in men but not in women. A female sex-related effect for the risk of PDD may be so strong that it overcomes any protective effect due to genetic factors.
authors.affiliation: Institute of Neurology, University ''Magna Graecia,'' Catanzaro, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Zappia
authors.forename: Grazia
authors.initials: G
authors.lastname: Annesi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nicoletti
authors.forename: Gennarina
authors.initials: G
authors.lastname: Arabia
authors.forename: Ferdinanda
authors.initials: F
authors.lastname: Annesi
authors.forename: Demetrio
authors.initials: D
authors.lastname: Messina
authors.forename: Pierfrancesco
authors.initials: P
authors.lastname: Pugliese
authors.forename: Patrizia
authors.initials: P
authors.lastname: Spadafora
authors.forename: Patrizia
authors.initials: P
authors.lastname: Tarantino
authors.forename: Sara
authors.initials: S
authors.lastname: Carrideo
authors.forename: Donatella
authors.initials: D
authors.lastname: Civitelli
authors.forename: Elvira V
authors.initials: EV
authors.lastname: De Marco
authors.forename: Innocenza C
authors.initials: IC
authors.lastname: Cirò-Candiano
authors.forename: Antonio
authors.initials: A
authors.lastname: Gambardella
authors.forename: Aldo
authors.initials: A
authors.lastname: Quattrone
mesh_terms: D017668:Age of Onset; D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D042622:DNA Repeat Expansion / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004409:Dyskinesia, Drug-Induced / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D007980:Levodopa / Q000009:adverse effects*; D008297:Male; D015999:Multivariate Analysis; D010300:Parkinson Disease / Q000188:drug therapy*; D011110:Polymorphism, Genetic / Q000235:genetics; D011237:Predictive Value of Tests; D017448:Receptors, Dopamine D2 / Q000235:genetics; D012727:Sex Characteristics
chemical_list: D000978:Antiparkinson Agents; D017448:Receptors, Dopamine D2; D007980:Levodopa