We present a case of a fatal Epstein-Barr infection in a 17-year-old male patient suspected to be caused by X-linked lymphoproliferative disease. At the time of hospitalization, DNA diagnostics was not available. The suspected diagnosis was confirmed several years later when a SH2D1A missense mutation was identified in stored patient DNA. Extended pedigree analysis showed that this mutation occurred de novo in his mother. In addition, we provide a summary of the currently listed SH2D1A mutations.
Conclusion: This case report underlines the importance of DNA storage, pedigree analysis, and multidisciplinary care in patients with rare diseases and their families.