Clinical aspects and molecular analysis of Chinese patients with Wiskott-Aldrich syndrome in Taiwan

Background: Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency, characterized by microthrombocytopenia, eczema and recurrent infections. More than 441 patient mutations have been described all over the world, mainly based on Caucasian and Japanese people. There have been few reported cases involving Chinese WAS patients. Objective: We investigated Chinese WAS patients in Taiwan since 1980. Methods: All WAS patients met the diagnosis criteria. Clinical manifestations, immunological functions, gene sequencing and the WAS protein (WASP) expression were analyzed. Results: Eleven male Chinese WAS patients were enrolled, presenting as classic WAS phenotype, correlative to the expression level of WASP and the severity of infections. Seven patients had autoimmune disorders, encompassing autoimmune hemolysis in 4, lymphoproliferative disorders in 2 and ulcerative colitis in 1 patient. As well as prophylactic monthly intravenous immunoglobulin infusion, splenectomy was performed on 2 patients. Five patients received hematopoietic stem cell transplantation. The causes of mortality were mass bleeding, sepsis and Epstein Barr virus-associated lymphoproliferative disorders in 3 nontransplant patients and acute graft failure and cytomegalovirus pneumonitis in 2 transplant patients. Nine patients received genetic analysis and revealed 4 unique mutations. None had the X-linked thrombocytopenia phenotype. Conclusions: All of the recognized Chinese WAS patients had the classic phenotype. Most mutations involved exon 1 of the WASP gene and none had the X-linked thrombocytopenia phenotype. This may be attributable to genetic variation, although selection bias may exist.