Wiskott Aldrich Syndrome-2 Caused by Novel Wiskott Aldrich Syndrome Protein–Interacting Protein (WIP) Deficiency Is Associated with Juvenile Myelomonocytic Leukaemia — a Case Report

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterised by microthrombocytopenia, eczema, and immunodeficiency, with a predisposition to autoimmunity and lymphoproliferative disease. A related but distinct condition, Wiskott-Aldrich syndrome 2 (WAS2), is an ultra rare autosomal recessive disorder caused by biallelic pathogenic variants in WIPF1, which encodes WASP-interacting protein (WIP). Only six cases of WAS2 had previously been described. Here, we report the seventh case of WAS2 with WIP deficiency and extend the known phenotype to include juvenile myelomonocytic leukaemia (JMML), a presentation recognised in WAS but not previously associated with WAS2.