Three cases report of X-linked thrombocytopenia and literature review

Abstract

Objective To further the understanding of the clinical features and molecular genetics of X-linked thrombocytopenia(XLT), facilitating early diagnosis. Methods From January 2012 to May 2014, three children with XLT were included in the study.The study protocol was approved by the Ethical Review Board of Investigation in Human Being of West China Second University Hospital, Sichuan University. Informed consent was obtained from each participants' parents.The clinical data and genotypes of the three cases of XLT who were diagnosed by WAS gene analysis were analyzed respectively. Results The 3 cases (100.0%) with XLT were all boys characterized clinically by chronic or intermittent thrombocytopenia, without positive family history.Before definite diagnosis of XLT via WAS gene mutation analysis, all 3 cases were misdiagnosed as primary immune thrombocytopenia(ITP) and were given steroid and intravenous immunoglobulin (IVIG) therapies, but resulting in persistent or intermittent thrombocytopenia. WAS gene mutation analysis revealed 2 types of missense mutation, c. 1378C>T located in extron 11 of case 1 and 3, while c. 256C>T located in extron 2 of case 2. The mothers harbored the same respective WAS gene mutations. Conclusions XLT, a mild form of WAS, caused by WAS gene mutations, is clinically characterized by chronic or intermittent microthrombocytopenia and is easily be misdiagnosed as ITP. With high clinical alertness of XLT, pediatricians should always considering the diagnostic possibility of XLT when faced with boys presenting with thrombocytopenia during infancy and toddler period, particularly with poor therapeutic responses to conventional steroid or IVIG therapy. Early diagnosis could possibly be made based on elaborate history-taking, dynamic monitoring of platelet count and mean platelet volume (MPV), WAS gene mutation analysis which is of great importance for the clinical management and prediction of prognosis. Key words: X-linked thrombocytopenia; Clinical features; Mutation