title: CNR2 functional variant (Q63R) influences childhood immune thrombocytopenic purpura.
abstract: Immune thrombocytopenic purpura is an acquired autoimmune disorder that is the most common cause of thrombocytopenia in children. The endocannabinoid system is involved in immune regulation. We evaluated a common missense variant (CAA/CGG; Q63R) of the gene encoding the cannabinoid receptor type 2 (GeneID 1269) in 190 children with immune thrombocytopenic purpura and 600 healthy controls. The allelic frequencies and genotype distribution of the polymorphism in the patients were significant compared to control samples (P=0.006 and P=0.0001, respectively). Interestingly, when acute and chronic immune thrombocytopenic purpura patients were analyzed separately with respect to controls, a significant overrepresentation of the RR genotype and of the R allele was observed only for the chronic form (P=0.00021 and P=0.011, respectively). The relative odds ratio suggested the risk of developing chronic form was more than double in immune thrombocytopenic purpura children homozygous for the variant (odds ratio=2.349, 95% CI: 1.544-3.573; P<0.001).
authors.affiliation: Department of Paediatrics, Second University of Naples, Naples, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossi
authors.forename: Silvia
authors.initials: S
authors.lastname: Mancusi
authors.forename: Giulia
authors.initials: G
authors.lastname: Bellini
authors.forename: Domenico
authors.initials: D
authors.lastname: Roberti
authors.forename: Francesca
authors.initials: F
authors.lastname: Punzo
authors.forename: Simona
authors.initials: S
authors.lastname: Vetrella
authors.forename: Sofia Maria Rosaria
authors.initials: SM
authors.lastname: Matarese
authors.forename: Bruno
authors.initials: B
authors.lastname: Nobili
authors.forename: Sabatino
authors.initials: S
authors.lastname: Maione
authors.forename: Silverio
authors.initials: S
authors.lastname: Perrotta
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007223:Infant; D020125:Mutation, Missense; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000235:genetics*; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics*
chemical_list: D043885:Receptor, Cannabinoid, CB2