Abstract
Many clinical, neuroimaging, neuropathological, epidemiological, and genetic data suggest a relationship between essential tremor (ET) and Parkinson's disease (PD). Several hypothesis-based gene association studies attempted to find a genetic association between these diseases. Recent case-control association studies in Chinese and Spanish populations showed a marginal association between the CD4 rs1922452 and CD4 rs951818 single nucleotide variants (SNVs) and the risk of PD. The proteins encoded by the CD4 and LAG3 genes have an important role in modulating inflammatory responses, and some recent data associated inflammatory markers to ET. This study investigates a possible association between the most common SNVs in the LAG3/CD4 genes and the risk of ET in the Spanish Caucasian population. We genotyped 267 patients diagnosed with familial ET and 270 age- and sex-matched controls using specific TaqMan assays for CD4 rs1922452, CD4 rs951818, and LAG3 rs870849 variants. We found a decreased risk for ET in carriers of the LAG3 rs870849 C/C genotype and the LAG3 rs870849C allelic variant exclusively in men. The mean age of onset of ET was not related to any of the variants studied. These data suggest no association of the gene variants studied with the overall risk for ET, except for a slight decrease in risk in male ET patients carrying the variant LAG3 rs870849C. However, such an association lost significance after correcting for multiple comparisons.