Mapping variants in HTLV-1 genome to analyze their impacts on the HAM/TSP development: A systematic review

The reasons that lead some individuals living with the Human T Lymphotropic Virus 1 (HTLV-1) to develop HAM/TSP are still unclear. To better understand the viral genetic factors that may be associated with the development of HAM/TSP, this study aims to evaluate the impact of HTLV-1 genome mutations on the development of this disease through a systematic review. This review followed the PRISMA guidelines and was registered in the PROSPERO database. The search for articles was performed in PMC, PubMed, Lilacs, SciELO, and Embase databases using the following search descriptors: HTLV-1, HAM/TSP, mutation, polymorphism, genetic variation, and sequenc*. From the 1,929 articles found in the search, 20 were selected according to the pre-defined inclusion and exclusion criteria. A total of 619 HAM/TSP cases were compared with 555 AC controls. The mutations possibly related to the disease progression were detected in hbz (R119Q), tax (A7959V), ORF-I (R88K, P86S, S69G, P45L, L40F, C39R, CR9Y), and gp46 (V247I, N93D, S72G) genetic regions. The data collected and analyzed here indicate that mutations in the HTLV-1 genome could play an important role in the chronic inflammatory state and may be related to the development of HAM/TSP.