We studied the allelic and genotype frequencies of the single nucleotide polymorphisms, such as GABRA4-rs2229940" genes_norm="2557">L26M (rs2229940" genes_norm="2557">Leu26Met, rs2229940), GABRE-S102A (Ser26Ala, rs1139916), and GABRQ-rs3810651" genes_norm="55879">I478F (Ile26Phe, rs3810651), in 200 patients with familial ET and 250 healthy controls using TaqMan genotyping.