Single Nucleotide Polymorphisms and Haplotype Analyses of Complex Medical Disorders

Gonzalez, Suzanne D., Doctor of Philosophy. Cell Biology and Genetics. Single Nucleotide Polymorphisms and Haplotype Analyses of Complex Medical Disorders. Number of Pages: 129. Number of Tables: 25. Number of Illustrations: 5. Number of Titles Included in References: 197. There has been great difficulty in identifying genes involved in complex disorders. The complex genetic basis of these diseases indicates that either several genes act together to cause disease, or genetic heterogeneity is present in the population. This dissertation was aimed at developing new assays to identify polymorphisms in novel candidate genes that potentially contribute to two classes of common complex disorders: psychiatric diseases and metabolic disorders. Genotyping assays were developed to investigate single nucleotide polymorphisms (SNPs) and haplotypes in complex genetic disorders using multiplexed SNP panels, restriction fragment length polymorphism technology, and cycle sequencing platforms. An introduction to the study is provided in Chapter 1. Manuscripts focus on association studies of candidate genes in Bipolar Disorder and Schizophrenia (Chapter 2), Type 2 Diabetes, Hypertension and Metabolic Syndrome (Chapter 3), and baseline blood pressure in African Americans (Chapter 4). The summary of these manuscripts (Chapter 5) describes the significant associations made between SNPs/haplotypes in psychiatric and metabolic complex genetic disorders. Significant genetic associations of SNPs within the PHLPP gene were detected among schizophrenics (Chapter 2). The G allele of SNP rs8087170 was associated with the control population with the T allele of SNP rs12966002 was found only in schizophrenics. A significant variance was detected at SNP rs12457020 between bipolar and schizophrenic datasets, as there was a 10 fold increase in the A allele in the bipolar group. Significant associations of ATP1A2 5’ SNPs C-1489T and G-1253A were detected in metabolic syndrome and hypertensive groups (Chapter 3). Haplotypes based on these 3 SNPs were significantly associated with metabolic syndrome and hypertensive populations. Four linked ATP1A2 SNPs, G3756C, G3853A, C3913T and C3915T, were associated with baseline blood pressure (Chapter 4). Haplotypes associated with blood pressure in an ethnic specific manner. GGCC associated with lower blood pressures, while haplotype GGTT associated with higher blood pressures in African Americans. These studies provide new mechanisms to identify mutations and provide evidence supporting the pathophysiology of these disorders.