haemophagocytic lymphohistiocytosis, familial, type 2

haemophagocytic lymphohistiocytosis, familial, type 2

A rare autosomal recessive disorder (OMIM:603553) characterised by immune dysregulation with hypercytokinaemia, defective NK cell activity, and massive infiltration of several organs by activated lymphocytes and macrophages.

Clinical findings
Fever, hepatosplenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenaemia; less commmonly, neurologic defects ranging from irritability and hypotonia to seizures, cranial nerve deficits and ataxia.

Molecular pathology
Defects in PRF1, which encodes a protein that plays a role in targeting and fusion of intracellular transport vesicles, cause familial haemophagocytic lymphohistiocytosis type 2.