TSPO gene polymorphism in Korean population

Abstract

AbstractBackground18‐kDA translocator protein (TSPO protein) expression increases in neuroinflammation. Specific ligands that binds to TSPO protein can be used to visualize neuroinflammation. Due to the reported dependency of binding properties of the second‐generation TSPO ligands on a genetic polymorphism of the TSPO gene, all individuals were genotyped and classified as low‐, medium‐, or high‐affinity binder (LAB, MAB, and HAB). The objective of this study is to investigate the rs6971 gene polymorphism in Korean population.MethodWe performed genetic testing in 109 subjects including Alzheimer’s disease, mild cognitive decline, Lewy body disease, subcortical vascular dementia, and cognitively unimpaired participants. All of them performed MRI and detailed neuropsychological test. 29 participants also took 18F‐DPA714 PET. Exon 4 of the TSPO gene containing the polymorphism rs6971 (Ala or Thr at position 147) as well as exon/intron junctions were PCR amplified and sequenced using Sanger method. The identified rs6971 genotypes (C/C, C/T, or T/T) code for the amino acids Ala/ Ala, Ala/Thr, or Thr/Thr at position 147 of the TSPO protein and were considered to generate a high‐, medium‐, or low‐affinity binding phenotype, respectively.ResultWe found 96.3% of the study subjects were HAB (105 out of 109 subjects), and 3.7% of the subjects were MAB (4 out of 109 subjects). There was no participant who was LAB. From HapMap data allele frequency, American group had 69.2%of HABs, 28% of MABs, and 2.8% of LABs. In African group, 67.4% was HABs, 29.4% was MABs, and 3.2% was LABs. In Asian group, 96.9% was HABs, 6.1% was MABs, and 0.1% was LABs. In Europe group, 45.7% was HABs, 43.8% was MABs, and 10.5% was LABs.ConclusionKorean population had lesser frequency of MABs and LABs like other Asian population. Therefore, availability of second‐generation TSPO PET related to rs6971 gene polymorphism would be lesser affected.