Association between restless legs syndrome and CLOCK and NPAS2 gene polymorphisms in schizophrenia. (August 2014)

• Record Type: Journal Article
• Authors: Jung, Jin-Sook; Lee, Heon-Jeong; Cho, Chul-Hyun; Kang, Seung-Gul; Yoon, Ho-Kyoung; Park, Young-Min; Moon, Joung-Ho; Yang, Hee-Jung; Song, Hyun-Mi; Kim, Leen
• Is Part Of: Chronobiology international. Volume 31:Number 7(2014)
• Page Start: 838
• Page End: 844
• Publication Date: 2014-08
• Subjects: Chronobiology -- Periodicals; Biological rhythms -- Periodicals; Circadian rhythms -- Periodicals; 571.77
• DOI: 10.3109/07420528.2014.914034
• Languages: English
• ISSNs: 0742-0528

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <p>Previous studies have suggested that there is a genetic basis to restless legs syndrome (RLS) development. Occurrence of antipsychotic-induced RLS could also be due to differences in genetic susceptibility. We investigated whether <italic>CLOCK</italic> and <italic>NPAS2</italic> gene polymorphisms are associated with RLS in schizophrenic patients on antipsychotics because RLS symptoms usually manifest during the evening and night. We assessed symptoms of RLS in 190 Korean schizophrenic patients on antipsychotics and divided the subjects into two groups according to the International Restless Legs Syndrome Study Group diagnostic criteria: (i) subjects who met all the criteria and (ii) the remaining subjects who did not meet all the criteria. We found a significant difference in the number of subjects with different genotype and allele carrier frequencies for the <italic>CLOCK</italic> gene (rs2412646) between the two groups (<italic>p</italic> = 0.031 and 0.010, respectively). Distribution of <italic>CLOCK</italic> haplotypes (rs2412646–rs1801260) was significantly different between schizophrenic patients with and without RLS (<italic>p</italic> = 0.021). However, the distributions of allelic, genotypic, and haplotypic variants of <italic>NPAS2</italic> (rs2305160 and rs6725296) were not significantly different between the two groups. Our results suggest that <italic>CLOCK</italic> polymorphisms are associated with increased susceptibility of schizophrenic patients to RLS. We hypothesize that RLS in schizophrenia patients treated with antipsychotics may be a very mild akathisia that manifests during the night and is under control of circadian oscillation.</p> </abstract>