In our study, the findings related to VDR FokI and TaqI variants observed in Hashimoto’s thyroiditis (FokI: 90%, TaqI: 50%), allergic diseases (FokI: 92.1%, TaqI: 71.1%), and ASD (FokI: 91.7%, TaqI: 66.7%) suggest that environmental and immunological factors play important roles in these conditions. The gene discussed is VDR; the disease is Hashimoto thyroiditis.