TNF and Posterior Leukoencephalopathy Syndrome: In particular, previous meta-analyses have shown that the risk of RPLs is significantly associated with the incidence of TNF-α −308G > A and − 238G > A polymorphisms in the overall population [25], while in another meta-analysis no association emerged between TNF-α −308G > A and RPL as investigated in Caucasian and Asian subjects [26].