A frequent polymorphism in the coding exon of the human cannabinoid receptor (CNR1) gene.

The central cannabinoid receptor (CB1) mediates the pharmacological activities of cannabis, the endogenous agonist anandamide and several synthetic agonists. The cloning of the human cannabinoid receptor (CNR1) gene facilitates molecular genetic studies in disorders like Gilles de la Tourette syndrome (GTS), obsessive compulsive disorder (OCD), Parkinsons disease, Alzheimers disease or other neuro psychiatric or neurological diseases, which may be predisposed or influenced by mutations or variants in the CNR1 gene. We detected a frequent silent mutation (1359G-->A) in codon 453 (Thr) of the CNR1 gene that turned out to be a common polymorphism in the German population. Allele frequencies of this polymorphism are 0.76 and 0.24, respectively. We developed a simple and rapid polymerase chain reaction (PCR)-based assay by artificial creation of a Msp I restriction site in amplified wild-type DNA (G-allele), which is destroyed by the silent mutation (A-allele). The intragenic CNR1 polymorphism 1359(G/A) should be useful for association studies in neuro psychiatric disorders which may be related to anandamide metabolism disturbances.