Expression of partial tandem duplication of mixed lineage leukaemia in patients with acute leukaemia and their relatives

Background Partial tandem duplication of mixed lineage leukaemia （MLL-PTD） is detected both in patients with acute leukemia and in healthy people.However,MLL-PTD in relatives of patients with MLL-PTD has not been reported.The objective of this study was to investigate the expression of MLL-PTD in patients with acute leukemia and in their relatives.Methods The bone marrow or peripheral blood was collected from patients with acute leukaemia and their relatives.Nested reverse transcription-polymerase chain reaction （RT-PCR） was applied to detect the mRNA expression of the MLL-PTD fused gene,and further confirm in genomic DNA level.Results Analysing MLL-PTD in case 1,the patient＇s older brother and his younger brother were positive,while his mother and his son were negative.The exon type in case 1 was e9/3 fusion,but in his older brother,it was e9/3 and e11/3 fusion,and in his younger brother,it was e9/3,e10/3,and e11/3 fusion.MLL-PTD in case 2 was negative,but in the patient＇s older sister was positive,and the exon type was e9/3,e10/3,and e11/3.Conclusions The expression of MLL-PTD was present in cases with acute leukaemia with a single expression type.However,various expression types were detected in their healthy relatives.MLL-PTD can couple with other chromosome aberrations,and its impact on disease prognosis remains to be studied further.