FcGR2A gene copy number variation and host susceptibility to vascular leakage in dengue infection / Qurratu Aini Puad

Dengue, the most rapidly spreading mosquito-borne viral disease in the world has been a major public health concern in Malaysia. According to the Ministry of Health, the incidence rate of dengue was 63.6 per 100 000 Malaysian population in 2011. Dengue deaths usually occur as a result of complication of severe vascular leakage. However, the exact mechanism of developing vascular leakage has still not been answered to universal satisfaction. Previous studies has reported the role of Fe gamma receptor 2A (FcGR2A) gene in mediating antibody dependent enhancement (ADE) pathway, leading to different clinical outcomes. In this study, we aimed to evaluate the association of FcGR2A gene copy number variation (CNV) with the presence of vascular leakage. The DNA was extracted from dengue patients' whole blood. CNV genotyping was employed by using quantitative PCR (qPCR) with TaqMan probe. The CNV calls that is CN normal, loss and gain were decided. Chi-square test was applied to determine the association of CNV calls with the susceptibility of vascular leakage. A total of 85 subjects were recruited (59 cases and 26 controls). We observed 19 subjects (13 cases, 6 controls) with CN gain. 11 subjects (7 cases, 4 controls) with CN loss. Whilst, the rest remained normal (CN=2). We suspect CNV of FcGR2A may not play a role in vascular leakage of dengue. Nonetheless, the hypothesis is not conclusive yet. Study with larger sample size and more advanced molecular technology are warranted to produce more convincing result.