Neonatal diagnosis has recently been improved through the identification by L’Ollivier et al. (2012) and Peyclit et al. (2023) of a pathognomonic marker for congenital toxoplasmosis: the IgM triplet, corresponding to three high molecular weight bands of 75, 90, and 100 kDa, respectively found on the mother-child immunoblot pair profile. The gene discussed is CD40LG; the disease is congenital toxoplasmosis.