RESUMEN
Perform gene [PRF1] mutations have been reported in 20-30% of patients with familial hemophagocytic lymphohistiocytosis [FHL], an immune disorder of infancy and early childhood. Cytotoxic T and natural killer [NK] cell activities are remarkably reduced or absent in FHL patients. We report the first cases of familial hemophagocytic lymphohistiocytosis in an Iranian family with two siblings. Exons 2 and 3 of the PRF1 gene were analyzed by polymerase chain reaction [PCR] amplification and direct sequencing. Perform gene mutation[s] were detected in none of the cases. The result of our study indicates that not much evidence is present concerning a correlation between perforin gene defects and familial hemophagocytic lymphohistiocytosis etiology in these cases