Genetics of restless legs syndrome: An update.

A major role of genetic factors in the risk of developing restless legs syndrome (RLS) is supported by the high frequency of positive family history of RLS in patients affected with this disease, and the higher concordance rates in monozygotic twins compared with dizygotic ones in twin studies. In this review we have focused on those reports describing inheritance patterns of RLS, genetic anticipation, the results of studies performed on positivity of family history of RLS, twin studies, linkage studies in familial RLS, genome-wide association studies (GWAS), exome sequencing studies, and case-control association studies on candidate genes in RLS. Although to date the causative gene(s) has(ve) not been definitively identified, a number of variants of several genes, most of them through GWAS, have been associated with RLS risk, the strongest candidates being variants of PTPRD, BTBD9, and MEIS1 genes. Despite results of several recent case-control association studies which have suggested a possible contribution of heme-oxygenase 1 (HMOX1) rs2071746 and vitamin D3 receptor (VDR) rs731236 variants, or the presence of allele 2 of the complex microsatellite repeat Rep1 within the alpha-synuclein (SNCA) gene promoter in modifying the risk for RLS, these studies need to be replicated in further studies involving different populations.