In this study, we identified three heterodimer-haplotypes (i.e., DQA1*03:03/DQB1*06:01, DQA1*01:03/DQB1*04:01, and DPA1*02:02/DPB1*09:01) as risk factors associated with CS incidence. The gene discussed is HLA-DPA1; the disease is Cowden syndrome 1.