For the OG, at recruitment, blood samples were collected from the new-borns and their mothers, and serum samples were tested for the presence of ZIKV (viral RNA and/or specific IgM), and TORCH agents (IgM and IgG for toxoplasmosis, rubella, cytomegalovirus (CMV), herpes simplex virus, syphilis) in order to rule out co-infections and/or to exclude other potential infectious causes of congenital microcephaly. This evidence concerns the gene CD40LG and syphilis.