SH2D1A and X-linked lymphoproliferative syndrome: Two other genes were affected by tandem duplications as part of the complex rearrangement (SV18, 19): SH2D1A, encodes an SH2 domain containing 1A protein (SAP), which has been associated with X-linked lymphoproliferative syndrome type 1 (XLP-1 [MIM: 308240]).