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. 2017 Oct 23;127(12):4270–4284. doi: 10.1172/JCI94455

Figure 6. SNP rs1998848 in NDRG2 exon 2 is associated with susceptibility to ADHD and suppression of NDRG2 expression.

Figure 6

(A) Fourteen polymorphic SNPs in a 10-kb region containing the NDRG2 gene. The rs1998848 SNP in exon 2 (star) is the only SNP associated with ADHD susceptibility. The numbers indicate the exon sequence. The open reading frame is located in exon 3. (B) The NDRG2 promoter, exon 1, and exon 2 with the major allele C (pGL3-C) or minor allele T (pGL3-T) of rs1998848 were inserted upstream of the luciferase reporter gene. The pGL3-basic vector (pGL3) was used as a negative control. (C) The relative luciferase activity (firefly luciferase/Renilla luciferase) of pGL3-C, pGL3-T, or pGL3 was analyzed in HEK293 cells. Luciferase activity experiments were performed in triplicate, and data were obtained from 3 independent measurements. *P < 0.05; **P < 0.01, 1-way ANOVA with Tukey-Kramer post hoc test. Error bars indicate mean ± SEM. (D) Relative levels of NDRG2 mRNA in the peripheral blood cells of the heterozygous (CT) patients (5 cases), homozygous (CC) patients (5 cases), and homozygous controls (5 cases). The values were normalized to β-actin, and control 1 was designated 1. Data were obtained from 3 independent measurements, and each experiment was performed in quadruplicate. **P < 0.01, 1-way ANOVA with the Tukey-Kramer post hoc test. Error bars indicate mean ± SEM.