Investigation of a Possible Role for the Histidine Decarboxylase Gene in Tourette Syndrome in the Chinese Han Population: A Family-Based Study

Tourette syndrome (TS) is a polygenic neuropsychiatric disease. Previous studies have indicated that dysregulation in the histaminergic system may play a crucial role in disease onset. In this study, we investigated the role of the histidine decarboxylase gene (HDC) in TS susceptibility in the Chinese Han population. After genotyping 241 TS nuclear families trios, we analyzed three tag HDC single nucleotide polymorphisms (rs854150, rs854151, and rs854157) in a family-based study using the transmission disequilibrium test (TDT) and haplotype relative risk (HRR). TDT showed no over-transmission in these SNPs across the HDC region (for rs854150: chi(2) = 0.472, P = 0.537, OR = 1.097, 95% CI = 0.738-1.630; for rs854151: chi(2) = 0.043, P = 0.889, OR = 1.145, 95% CI = 0.767-1.709; for rs854157: chi(2) = 0.984, P = 0.367, OR = 1.020, 95% CI = 0.508-2.049). HRR also showed the same tendency (for rs854150: chi(2) = 0.211, P = 0.646, OR = 1.088, 95% CI = 0.7591.559; for rs854151: chi(2) = 0.134, P = 0.714, OR = 0.935, 95% CI = 0.653-1.339; for rs854157: chi(2) = 0.841, P = 0.359, OR = 1.206, 95% CI = 0.808-1.799). Additionally, the haplo-type-based haplotype relative risk showed a negative association. Although these findings indicate an unlikely association between HDC and TS in the Chinese Han population, a potential role for HDC cannot be ruled out in TS etiology. Future research should investigate this more thoroughly using different populations and larger samples.