In summary: (a) our GWAS study of thyroid volume in HT patients identified association of two genetic variants in AATF/SMARCA2, thus implying that regulation of thyroid volume of patients with HT has a genetic component; (b) further analysis of expression patterns showed differential expression levels of AATF and SMARCA2 between HT cases and controls of the same genotype accompanied by significantly increased apoptosis in HT patients, further suggesting their role in pathophysiological processes of thyroid gland of HT patients. The gene discussed is SMARCA2; the disease is hematocrit.