Identification of Novel Mutations In Adenosine Deaminase Gene In Korean Leukemia Patients

Abstract

Leukemia is the abnormal increase of hematopoietic progenitor cells in tissues, resulting in anemia, increased susceptibility to infection and impaired blood clotting. The adenosine deaminase (ADA) gene is an important druggable target for the treatment of leukemia patients. Genetic and molecular analyses were performed to determine the effects of ADA gene mutations in 20 leukemia patients in the Korean population. To analyze the relationship between genotype and phenotype, the ADA genomic DNAs -including 1,092 bp of 12 exons and partial intron sequences flanking each exon -were sequenced and compared. In this study, the known mutations in other diseases, more than 50 mutations already reported in patients with severe combined immunodeficiency disease (SCID) and autism, were not found, but two novel mutations in leukemia patients were discovered. They include one nonsense mutation (A>C at nt position 478, F101F) and one missense mutation (G>A at nt position 778, E260K). One missense mutation (G>A at nt position 22, D8Y) was also detected in 20 normal control patients (allelic frequency of 7.5%). Interestingly, subjects in the Korean population retained 2 bp insertion at the intron 6 (IVS6-52insGC), something that has never been shown in other populations. The genetic study to find out the correlation between the mutant alleles and leukemia patients revealed no association statistically (p>0.05). The mutation found in leukemia needs further study to determine its possibility as a molecular marker for the diagnosis of leukemia.