This information explains the rare immune condition called X-linked lymphoproliferative type 1 (XLP1) disorder.
XLP1 is also known as Duncan’s disease, SAP deficiency and classic XLP.
Type 2 XLP is quite different from type 1 and is described separately here.
The content has been produced jointly between Immunodeficiency UK, Great Ormond Street Hospital (GOSH) and the Great North Children’s Hospital and in association with the XLP Research Trust. The information has been reviewed by our Patient Representative Panel and by families affected by XLP1.