Genetic association between schizophrenia and type-2 diabetes

  • Aditi Mathur

Student thesis: Doctoral ThesisDoctor of Philosophy (awarded by OU/Aberdeen)


Background and aims: It has long been noted that there is a close link between schizophrenia and type-2 diabetes (T2D). Patients with schizophrenia have a high risk of T2D. In order to clarify a genetic association between these two conditions, this study was designed to investigate a genetic pathway that might be associated with both schizophrenia and T2D, and to explore whether clozapine could affect expression of the genes associated with obesity and T2D.
Methods: A total of 221 British nuclear families consisting of 148 fathers, 204 mothers and 222 affected offspring with schizophrenia were recruited for the genetic analysis. All family members studied were of Caucasian descent, including English, Welsh, Irish and Scottish individuals. The genetic analysis genotyped a total of 17 single nucleotide polymorphisms (SNPs) in the genes coding for peroxisome proliferator activated receptor-gamma (PPARG), phospholipid A2, group IVA (PLA2G4A), prostaglandin-endoperoxide synthase 2 (PTGS2) and v-akt murine thymoma viral oncogene homolog 1 (AKT1). The Haploview™ program was applied to check Mendelian errors, to test Hardy-Weinberg equilibrium (HWE) and to estimate linkage disequilibrium (LD) between paired SNPs. Analysis for allelic and haplotypic associations and for the gene-gene interaction was performed with the UNPHASED program using likelihood-based association analysis for nuclear families with missing parental genotype data. In the functional study, U937 cells were cultured and treated with clozapine (1μg/ml and 2μg/ml) for 48 hours and 96 hours,
respectively. Quantitative real-time PCR analysis was used to measure the mRNA
expression levels of the genes of interest. A relative quantification method (the
comparative Ct method; 2-ΔΔCt) was used to analyze the differences in gene
expression between clozapine-treated and untreated cells. Two house-keeping
genes (HKGs), beta-actin (ACTB) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were used as the internal controls to normalize the Ct values of the target genes. Fisher’s combining probability test was used to determine the combined p values from the Student’s t-tests for two HKG-normalized results.
Date of Award25 Nov 2011
Original languageEnglish
Awarding Institution
  • University of Edinburgh
SupervisorJun Wei (Supervisor), Ian Megson (Supervisor), Duncan J Shaw (Supervisor) & Matthew Law (Supervisor)

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