PRF1 and hemophagocytic syndrome: Our patient harbored a homozygous missense mutation, c.1349C > T (p.Thr450Met), of PRF1 gene, which was classified as pathogenic variant associated with familial HLH (Barmettler et al., 2016; Sun et al., 2014; Wang et al., 2014) and has been previously described in patients with CNS-HLH (Borda et al., 2024; Feng et al., 2020).