INTERDISCIPLINARY STUDIES: NEUROGENETICS ASSOCIATION STUDY OF TWO SLC6A4 POLYMORPHISMS WITH AUTISM JACQUELYN RECKTENWALD Thesis under the direction of Professor James Sutcliffe Autism is a heritable neurodevelopmental disorder characterized by impairments in language development and use, social interaction and repetitive behaviors, restricted interests and resistance to change. Serotonergic system dysregulation is implicated in autism since ~25% of individuals with autism have blood platelet hyperserotonemia, selective serotonin reuptake inhibitors are efficacious in treating repetitive behaviors, anger and anxiety in autism, and PET studies indicate children with autism have less capacity for CNS serotonin synthesis than children without autism. These findings indicate the serotonin transporter (SERT) as a strong candidate susceptibility gene and studies point toward linkage in a region containing the SERT gene (SLC6A4) locus with autism. Two SLC6A4 repeat polymorphisms, HTTLPR and VNTR, are located in the promoter region upstream of SLC6A4 and in the second intron, respectively, and regulate SERT expression. Association studies of HTTLPR or VNTR polymorphisms with autism are inconclusive. We hypothesized that there would be preferential transmission of an HTTLPR polymorphism, VNTR polymorphism and a haplotype containing these polymorphisms to affected individuals in our sample. We found no association of any HTTLPR polymorphisms or VNTR polymorphisms with autism in our sample and further we did not find any association of a haplotype containing these polymorphisms with autism in our sample. Paternal inheritance of VNTR alleles was associated with the social intent and milestones (p =.02 and p = .05, respectively) components of the ADI-R, however, these two association results may be due to chance.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Ana Campos. Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Ana Campos. Includes bibliographical references. Also available via World Wide Web.

Thesis (M. Phil.)--City University of Hong Kong, 2005. / "Submitted to Department of Biology and Chemistry in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references.

Migraine is a highly prevalent headache disorder imposing a significant burden of disability on human health worldwide. The headache is believed to arise from activation of trigeminal pain pathways, with CNS regions also playing an integral role in attack initiation and progression. Recent genetic associations have been made, but there is a need to convert these into relevant experimental models to study underlying disease mechanisms. Herein, I detail functional analysis of two deleterious variants in the genes KCNK18 and SLC12A3, that segregate with migraine with aura in one large pedigree. Gene function has been studied in a range of cell models, from heterologous expression systems and primary neuronal cultures, to Induced Pluripotent Stem (iPS) cell-derived nociceptors. In this context, the protein products of KCNK18 and SLC12A3 have been shown to modulate parameters of neuronal excitability, including baseline membrane properties and firing patterns. Migraine attacks are not wholly attributable to perturbations in peripheral pathways. I have shown that these genes are also expressed within the CNS in a small number of discreet regions, suggesting a possible role in central processing. Utilizing recently defined genetic variants and physiological cell- based models, will provide a platform for mechanistic insights into migraine pathogenesis and allow for the development of drug screening assays for new migraine therapies.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 76-80).

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiv, 111 p.; also includes graphics (some col.). Includes bibliographical references (p. 98-111). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 106-135).

Thesis (Ph.D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 106-135) Also available in print.

Rare diseases caused by single-gene mutations affect almost one million Canadians. According to the Online Mendelian Inheritance in Man database, ~4,500 rare monogenic diseases have a known cause; but less than 5% of patients have access to disease-modifying drugs. The dearth of accessible drugs for patients suffering from rare genetic diseases is partly due to the astronomical costs of traditional drug development which, when combined with the small target population, make rare disease therapeutics unattractive ventures for the pharmaceutical establishment. The paucity of cost-effective treatments for rare diseases has resulted in the promotion of clinic-ready drug repurposing as a tenable strategy for rare disease therapeutics. To identify repurposed candidates for rare neurogenetic diseases, I conducted a transcriptome-wide drug screen in mouse primary cerebrocortical cultures. RNA sequencing was used to develop a database of transcriptome-wide differential expression for 218 clinic-tested drugs. The “Neuron Screen” database was queried to identify drugs that upregulate ~60 rare neurogenetic disease genes (type I hits). Gene set enrichment pathway analysis by Ingenuity Pathway Analysis (IPA) was used to identify network associated drug-gene interactions (type II hits). Both types of drug-gene hits were further assessed in vitro and in vivo by qRT-PCR and western blot analysis. This analysis showed that the IPA-based network-associated approach reduces the false positive rate when identifying differentially expressed genes in transcriptome-wide data-sets. The analysis also identified two drug-gene interactions with genes that cause rare neurogenetic disease, thyroid hormone-Pmp22 and dexamethasone-Mfsd2a, that merit further investigation. This work proves the utility of the Neuron Screen database to connect rare disease genes with transcript-modulating drugs and provides a starting point to understand the transcriptional effects of pharmacologic agents on the mammalian brain.