CNTN2 and infection: Furthermore, Caterino-de-Araújo and Rodrigues Campos (33) described difficulties in the laboratory diagnosis of the infection, including the presence of incomplete HTLV viral particles (characterized by the absence of a viral gene, such as the tax gene), low quality of extracted DNA, mutations and a low proviral load, which can potentially lead to the absence of gene amplification and thus result in a false-negative diagnosis for infection.