Abstract
Hemophagocytic lymphohistocytosis (HLH) is a severe and fatal immunological disorder that is either primary (i.e., familial) or secondary (i.e., acquired). The primary type comprises autosomal recessive disorders with gene mutations related to natural killer cells and cytotoxic T-cells, whereas the secondary type is related to other pathological causes, such as Epstein-Barr virus, bacterial or fungal infection, autoimmune conditions or autoinflammatory diseases, metabolic disorders, and cancer. In this report, we discuss a 37-day-old male who was brought to the emergency room with fever, decreased activity, and hepatosplenomegaly, with a strong family history of unknown cause of death for three siblings who died at the ages of one to two months. A whole exome sequencing confirmed the clinical diagnosis of familial HLH due to mutation in the PRF1 gene. We note the special importance of genetic counselling and antenatal screening or early neonatal screening in families affected by HLH, as this case highlights the importance of early diagnosis and intervention of primary HLH.