Association study between antipsychotics- induced restless legs syndrome and polymorphisms of dopamine D1, D2, D3, and D4 receptor genes in schizophrenia.

OBJECTIVE

The cause of restless legs syndrome (RLS) is not yet clear, but more promising theories involve dopaminergic deficiency and genetic causes. This study investigated whether single-nucleotide polymorphisms in the genes of dopamine receptors DRD1, DRD2, DRD3 and DRD4 are associated with antipsychotics-induced RLS in schizophrenia.

METHODS

We evaluated 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group and its rating scale for RLS. Genotyping was performed for the DRD1 gene -48A/G, DRD2 gene TaqI A, DRD3 gene Ser9Gly and DRD4 gene -521C/T single-nucleotide polymorphisms. The method of multifactor dimensionality reduction was used to analyze gene-gene interactions.

RESULTS

We classified the schizophrenic patients into 96 with and 94 without RLS symptoms. The genotype frequencies of all polymorphisms investigated did not differ significantly between these 2 groups. MDR analysis did not show a significant effect of the 4 dopamine receptor gene variants on susceptibility to antipsychotic-induced RLS symptoms (p > 0.05).

CONCLUSIONS

These genetics data suggest that the analyzed polymorphisms of the dopamine genes may not be associated with RLS symptoms in schizophrenia. Confirming the results reported here requires a larger-scale study involving patients taking specific antipsychotics.