title: Lower frequency of the low activity adenosine deaminase allelic variant (ADA1*2) in schizophrenic patients.
abstract: OBJECTIVE
  Adenosine may play a role in the pathophysiology of schizophrenia, since it modulates the release of several neurotransmitters such as glutamate, dopamine, serotonin and acetylcholine, decreases neuronal activity by pos-synaptic hyperpolarization and inhibits dopaminergic activity. Adenosine deaminase participates in purine metabolism by converting adenosine into inosine. The most frequent functional polymorphism of adenosine deaminase (22G→A) (ADA1*2) exhibits 20-30% lower enzymatic activity in individuals with the G/A genotype than individuals with the G/G genotype. The aim of this study was to evaluate the ADA polymorphism 22G→A (ADA1*2) in schizophrenic patients and healthy controls.
  
  
  METHODS
  The genotypes of the ADA 22G→A were identified with allele-specific PCR strategy in 152 schizophrenic patients and 111 healthy individuals.
  
  
  RESULTS
  A significant decrease in the frequency of the G/A genotype was seen in schizophrenic patients (7/152 - 4.6%) relative to controls (13/111 - 11.7%, p = 0.032, OR = 2.6).
  
  
  CONCLUSIONS
  These results suggest that the G/A genotype associated with low adenosine deaminase activity and, supposingly, with higher adenosine levels is less frequent among schizophrenic patients.
authors.affiliation: Department of Celular and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Gustavo Pimentel
authors.initials: GP
authors.lastname: Dutra
authors.forename: Gustavo L
authors.initials: GL
authors.lastname: Ottoni
authors.forename: Diogo R
authors.initials: DR
authors.lastname: Lara
authors.forename: Maurício Reis
authors.initials: MR
authors.lastname: Bogo
mesh_terms: D000243:Adenosine Deaminase / Q000235:genetics* / Q000502:physiology; D000328:Adult; D000483:Alleles; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D012559:Schizophrenia / Q000201:enzymology* / Q000503:physiopathology
chemical_list: D000243:Adenosine Deaminase