Lymphoproliferative Syndrome 1

**Semantic type:** Disease or Syndrome

**Definition:** An autosomal recessive immunodeficiency caused but mutation(s) in the ITK gene, encoding tyrosine-protein kinase ITK/TSK. It is characterized by the early childhood onset of Epstein-Barr virus (EBV)-associated immune dysregulation leading to lymphoma, lymphomatoid granulomatosis, hemophagocytic lymphohistiocytosis, and/or hypogammaglobulinemia.

**Synonyms:** - IL-2 Inducible T-cell Kinase Deficiency - ITK Deficiency - LPFS1 - Lymphoproliferative Syndrome 1/ITK Deficiency