The human amylase gene locus at chromosome 1p21.1 is structurally complex. This region contains two pancreatic amylase genes, AMY2B, AMY2A, and a salivary gene AMY1. The AMY1 gene harbors extensive copy number variation (CNV), and recent studies have implicated this variation in adaptation to starch-rich diets and in association to obesity for European and Asian populations. In this study, we showed that by combining quantitative PCR and digital PCR, coupled with careful experimental design and calibration, we can improve the resolution of genotyping CNV with high copy numbers (CNs). In two East Asian populations of Chinese and Malay ethnicity studied, we observed a unique non-normal distribution of AMY1 diploid CN genotypes with even:odd CNs ratio of 4.5 (3.3-4.7), and an association between the common AMY2A CN = 2 genotype and odd CNs of AMY1, that could be explained by the underlying haplotypic structure. In two further case-control cohorts (n = 932 and 145, for Chinese and Malays, respectively), we did not observe the previously reported association between AMY1 and obesity or body mass index. Improved methods for accurately genotyping multiallelic CNV loci and understanding the haplotype complexity at the AMY1 locus are necessary for population genetics and association studies.

The aim of the study is to investigate the association of vitamin D receptor (VDR) gene polymorphism, additional gene-gene interaction, and haplotype combination with systemic lupus erythematosus (SLE) risk. Pairwise linkage disequilibrium (LD) analysis was conducted using SNPstats. The association between four SNPs within VDR gene and SLE risk was investigated by logistic regression. Generalized multifactor dimensionality reduction (GMDR) was used to analyze the interaction among four SNPs. Four SNPs within VDR gene were selected for genotyping in this study, including rs2228570, rs1544410, rs7975232, and rs731236. The T allele of rs2228570 and the G allele of the rs1544410 were associated with increased MM risk, adjusted ORs (95%CI) were 1.61(1.25-2.11) and 1.78 (1.34-2.23), respectively. GMDR analysis suggested a significant two-locus model (P = 0.0010) involving rs1544410 and rs2228570, and in this model, the cross-validation consistency was 10/10, and the testing accuracy was 62.70%. The haplotype analysis indicated that the most common haplotype was rs1544410-A and rs7975232-G haplotype, the frequencies of which were 0.4701 and 0.5467 in case and control group. Haplotype containing the rs1544410-G and rs7975232-T alleles were associated with increased SLE risk, OR (95%CI) = 2.08 (1.47-2.72), P < 0.001. We found that rs2228570 and rs1544410 within VDR gene, their interaction and haplotype containing the rs1544410-G and rs7975232-T alleles were all associated with increased SLE risk.

Gene therapy has emerged as a promising approach for the lethal disorder of Duchenne muscular dystrophy (DMD). Using a novel non-viral delivery system, the human ribosomal DNA (hrDNA) targeting vector, we targeted a minidystrophin-GFP fusion gene into the hrDNA locus of HT1080 cells with a high site-specific integrated efficiency of 10 25, in which the transgene could express efficiently and continuously. The minidystrophin-GFP fusion protein was easily found to localize on the plasma membrane of HT1080 cells, indicating its possible physiologic performance. Our findings showed that the hrDNAtargeting vector might be highly useful for DMD gene therapy study.

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