Contribution of miR-124 rs531564 polymorphism to the occurrence of congenital Zika syndrome

Zika virus (ZIKV) cause Congenital Zika Syndrome (CZS) in individuals exposed during pregnancy. Studies have shown that ZIKV infection positively regulates the miR-124 expression in neural cells, which leads to a decrease of TFRC, a gene targeted of this miRNA. Both miR-124 and TFRC exhibit a pivotal role in nervous system development. Therefore, in this study we aimed to investigate whether genetic variants that affect the expression of these genes could act together with ZIKV to increase the risk of individuals developing CZS. TFRC rs406271 and MIR-124-1 rs531564 polymorphisms were genotyped, using TaqMan® Genotyping Assays, in a sample of children who were exposed to ZIKV during pregnancy, of whom 40 were born with CZS and 48 without congenital anomalies. We identified that individuals with CZS presented a higher frequency of CG genotype of rs531564 polymorphism in MIR-124-1 (p=0.048), which is associated with increased expression of miR-124. Since ZIKV also upregulates the expression of this miRNA, the presence of CG genotype in individuals exposed to the virus could lead to a scenario of overexpression of miR-124 in the brain. Since teratogenesis is a multifactorial event, this genetic finding could partly explain why such individuals are more susceptible to CZS, considering both the downregulation of important neurodevelopment genes, as well as deregulation of the neurogenesis process. Thus, we provide preliminary evidence about a possible genetic risk factor to CZS and highlight the importance of analyzing functional polymorphisms related to epigenetic modulators of neurodevelopment genes in the context of ZIKV teratogenesis.