Thiopurine methyltransferase (TPMT) risk alleles (mainly *2,*3B, *3C and *3A) are the major determinants of interindividual differences in the severe toxicity or efficacy of 6-mercaptopurine (6MP) during the treatment of childhood acute lymphoblastic leukemia (ALL). The frequencies of these risk alleles, known to functionally impair TPMT activity, were investigated among 167children with ALL and 206 healthy adult controls in Turkish population by using allele specific PCR and PCRRFLP methods. TPMT*3A and TPMT*3C were the only deficiency alleles detected in Turkish population with an allele frequency of 0.5% for both. The total frequency of mutant TPMT alleles in Turkish population (1.0%) was found to be significantly lower than those of other Caucasian populations (5.3-7.0%), but it was found to be very similar to Kazak population (1.2%) which is also Caucasian in ethnic origin. v In the patient group, two individuals were found to be heterozygote for *3C and *3A allele. One individual was homozygous mutant (*3B/*3C). In this study, the clinical histories of the patients with TPMT defects were examined retrospectively from hospital records. The patients with heterozygous or homozygous mutant genotypes had systematically developed severe neutropenia, infection and some other specific conditions (like lesions around mouth, oral herpes and high fever) when they were administered with 6MP during the therapy. This study provides the first data on the frequency of common TPMT risk alleles in the Turkish population, based on analysis of pediatric patients with ALL. The results would contribute valuable information to the public health, as more clinicians and patients become aware of the importance of TPMT polymorphisms, less patients will suffer from 6MP related adverse effects. In addition, in this study two genes EPHX1-microsomal epoxide hydrolase (exon 3 and exon 4 polymorphisms) and SULT1A1*2 variant &ndash / sulfotransferase 1A1, either alone or in combination were investigated as risk modifiers in the development of childhood acute lymphoblastic leukemia due to their dual role (activation/detoxification) in the metabolism of various carcinogens. Also interactions of these polymorphisms with non-genetic risk factors (parental smoking exposure and parental age at conception) were investigated. The conclusion inferred from results was that only genetically reduced EPHX1 activity (homozygous mutant genotype for EPHX1 exon 3 polymorphism and some specific genotype combinations with exon 4 polymorphism) was found to be significantly associated with the risk of childhood ALL.

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 115-127.

Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / "May 2001." Typescript. Vita. Includes bibliographical references (leaves 145-152). Also available on the Internet.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Thesis (Ph.D. in Immunology) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 153-162). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

CYP2D6, a member of the cytochrome P450 enzyme system, has a central role in drug metabolism, it metabolizes 25 % of clinically used drugs. The gene that codes for the enzyme displays a high degree of polymorphism, which effects enzyme functions to various degrees. Aside from smaller mutations like SNPs, alleles may also feature duplications or deletion of the whole gene. Due to the clinical relevance of these mutations, a simple and precise method for genotyping is needed. In this study, a method based on pyrosequencing for copy number analysis was evaluated, wherein the copy number was determined by relative quantification to a reference gene CYP2D8P. During evaluation of the method, several adjustments were tried for optimization, including adjustments of annealing temperature and primer concentration. The results showed a difficulty in distinguishing between copy numbers using the method, as well as a high coefficient of variation. Therefore, further optimization is required before the method could be implemented into clinical practice.

Genetic and functional studies have demonstrated that KIR gene polymorphism, including different haplotypes, allelic polymorphisms and different expression levels of KIRs, may all play a part in the association with HIV-1 infection outcome. Currently, there are very few studies focusing on the association between KIR and HIV in the Chinese population. In this project, we started to look at the polymorphism of KIRs in a unique chronic HIV-1 infected cohort (SM cohort), evaluating the impact of KIR and KIR-HLA interactions in terms of HIV-1 infection progression. The SM cohort is unique because the major factors such as viral strain, transmission route and timing of infection, which could affect the natural history of HIV-1, have been narrowly controlled. Through comparison with a healthy control population, some genetic associations were identified. The frequency of KIR2DL3 was lower in the “slow progressors” group; the compound genotype of KIR3DS1+ Bw4 homozygotes was significantly lower in the “slow progressors” group; additionally, group B genotypes (multiple activating genes) were shown to be likely to mount a greater immune pressure on HIV-1. In terms of KIR footprints, several amino acid positions were identified for which the substitution of an amino acid may be ascribed to the immune response from KIR-modulated NK cells rather than from HLA restricted CTL immune pressure. In Chapter 4, we report a novel method to sequence the entire locus of KIR3DL1/S1. Two specific pairs of primers have been successfully designed and tested to amplify KIR3DL1 and KIR3DS1 exclusively. Using this novel sequencing method, we showed the polymorphism of this locus at a 6-digit level. 8 new KIR3DS1 alleles, 12 new KIR3DL1 alleles, 1 new KIR3DL1 gene and 1 new KIR3DS1 gene have been identified in this study. In Chapter 5, we used a valuable acute HIV-1 infection cohort to further study associations between KIRs and the clinical outcomes. It was interesting to find that the frequency of KIR3DS1 was significantly lower in the slow progressors group (31%) than in the acute group (40.7%), which implies that KIR3DS1 plays a role in HIV-1 disease progression. There are two other trends demonstrated in this study. One trend was that positive KIR2DL2 and/or KIR2DS2 (they are in strong linkage disequilibrium with each other) were associated with a higher set point viral load (at 3 month) (p=0.06). Another trend was that KIR3DS1 might have an association with disease progression (p=0.057). Overall, in this study, the role of KIRs and KIR/HLA interactions were evaluated in acute and chronic HIV-1 infection, which has provided important information for further study.

Gene trapping has emerged as a valuable tool to create conditional alleles in various model organisms. Here we report the FLEx‐based gene trap vector SAGFLEx that allows the generation of conditional mutations in zebrafish by gene‐trap mutagenesis. The SAGFLEx gene‐trap cassette comprises the rabbit β‐globin splice acceptor and the coding sequence of GFP, flanked by pairs of inversely oriented heterotypic target sites for the site‐specific recombinases Cre and Flp. Insertion of the gene‐trap cassette into endogenous genes can result in conditional mutations that are stably inverted by Cre and Flp, respectively. To test the functionality of this system we performed a pilot screen and analyzed the insertion of the gene‐trap cassette into the lima1a gene locus. In this lima1a allele, GFP expression faithfully recapitulated the endogenous lima1a expression and resulted in a complete knockout of the gene in homozygosity. Application of either Cre or Flp was able to mediate the stable inversion of the gene trap cassette and showed the ability to conditionally rescue or reintroduce the gene inactivation. Combined with pharmacologically inducible site specific recombinases the SAGFLEx vector insertions will enable precise conditional knockout studies in a spatial‐ and temporal‐controlled manner.