Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Pre-eclampsia is a condition unique to pregnancy and primarily affects the maternal and placental vascular endothelium. It has significant morbidity and mortality consequences for both mother and infant. Despite global research into the aetiology of the condition, the cause for this condition remains unknown. Several factors, including a strong family history of hypertension in pregnancy point to a familial or genetic component in the pathophysiology of this complication. The purpose of this research project was to investigate candidate genes implicated in endothelial damage. Common methylene-tetra-hydrofolate reductase (MTHFR) gene mutations C677T and A1298C, factor V Leiden mutation R506Q and prothrombin mutation A20210G were investigated in 50 patients with an uncomplicated pregnancy outcome (controls) and 350 patients with various clinical manifestations of preeclampsia, including severe, early onset forms and abruptio placentae. Fasting homocystein levels were determined biochemically on all participants. In addition, 126 consecutive pregnant patients were recruited at booking, fasting lipograms were performed on them as well as mutation screening of 7 common mutations in the low-density lipoprotein receptor gene. This was correlated with eventual pregnancy outcome, and those with an uncomplicated outcome were selected as an additional control group. A significant association between hyperhomocysteinaemia and early onset severe pre-eclampsia could be demonstrated. Mutant allele T of the C677T mutation could be associated with hyperhomocysteinaemia but not with pre-eclampsia whilst mutant allele C of mutation A1298C demonstrated a significant correlation with diastolic blood pressure. In addition, combined heterozygosity for these mutations may serve as a marker for abruptio placentae. / ENGLISH ABSTRACT: Pre-eklampsie is 'n hipertensiewe toestand uniek aan menslike swangerskap en dit affekteer hoofsaaklik die vaskulêre endoteel. Die toestand hou ernstige morbiditeit en mortaliteit vir beide ma en baba in en na jare se navorsing is die oorsaak van hierdie toestand steeds onbekend. Epidemiologiese studies toon 'n duidelike familiële verband aan wat die vermoede laat ontstaan dat daar 'n onderliggende genetiese aspek tot die ontwikkeling van die siektetoestand is. Die doel van hierdie navorsingsprojek was om gene te ondersoek wat geïmpliseer word in endoteel skade. Twee algemene mutasies, C677T en A1298C in die MTHFR geen asook faktor V Leiden R506Q en protrombien A20210G mutasies is ontleed in 50 pasiënte met 'n ongekompliseerde swangerskapsverloop en in 350 pasiënte met 'n swangerskap gekompliseer deur verskillende kliniese manifestasies van die siekteproses, insluitende vroeë aankoms erge pre-eklampsie en abruptio placentae. Op alle pasiënte is ook 'n vastende homosistiën vlak biochemies bepaal. 'n Verdere 126 opeenvolgende pasiënte is gewerf tydens hulle eerste besoek aan die voorgeboortekliniek en vastende lipogramme is op almal uitgevoer. Mutasie sifting vir 7 algemene mutasies in die lae-digtheids lipoproteïen reseptor geen is op hierdie groep gedoen en die resultaat is met die uiteindelike swangerskapsuitkoms gekorreleer. Pasiënte met 'n uitkoms ongekompliseer deur hipertensie is gekies om deel te wees van 'n verdere kontrolegroep. Daar was 'n betekenisvolle verband tussen hiperhomositiënemie en erge, vroeë aankoms pre-eklampsie. Die T alleel van die C677T mutasie is geassosieer met hiperhomosistiënemie maar nie met pre-eklampsie nie. Die C alleel van die A 1298C mutasie toon 'n betekenisvolle verband met diastoliese bloeddruk. Gekombineerde heterosigositeit vir beide MTHFR mutasies kan 'n moontlike merker vir abruptio placentae wees.

Thesis (MSc (Genetics))—University of Stellenbosch, 2007. / In South Africa, pre-eclampsia is the second highest cause of maternal deaths. The incidence of this disease in the Western Cape alone is 6.8% and places a large burden of health care facilities. The placenta and implantation thereof is thought to play the most significant role in the onset of this disease. Among the many theories for its aetiology, is the acknowledged two - stage theory. This is based on evidence that pre-eclamptic placentas demonstrate altered remodelling and invasion into the uterine endometrium and myometrium. The sub-optimal endometrium invasion leads to less oxygenation of the placental environment causing transient hypoxia. Consequently, the placenta is thought to release unknown factors into the maternal circulation which then culminates in clinical features associated with pre-eclampsia. Neurokinin B is thought to be one of these placental factors and subsequently binds to the NKB receptor in the maternal system. Endothelium-derived nitric oxide synthase has recently been shown to activate this receptor. The aim of this study was to investigate the role of neurokinin B (TAC3) and the neurokinin B receptor (TACR3) genes in the predisposition of pre-eclampsia and their interaction with eNOS in the South African coloured population together with a matched control cohort.

Thesis (MSc (Genetics))--University of Stellenbosch, 2006. / Pre-eclampsia is a multisystemic disorder with an incidence of ~6-8% in non-Caucasian women in the Western Cape. Trophoblast invasion is vital for adequate anchorage of the placenta to the uterine wall as well as for the optimisation of utero-placental blood flow in uncomplicated pregnancies. This process is facilitated by the fetal trophoblast cells that digest the extracellular matrix of the uterus by secreting various molecules, including the metalloproteinases (MMP), of which MMP-9 has an increased production during the first trimester. Leptin, an autocrine regulator of MMP-9 secretion, functions via the leptin receptor to prevent over-invasion of maternal tissues. The aim of this study was to investigate the role of the leptin (ob) and leptin receptor (obR) genes in predisposition to pre-eclampsia and involved screening the genes in South African non-Caucasian cohorts and performing statistical analysis to determine whether any variants contributed to the disease profile.

Thesis (MSc (Genetics))--University of Stellenbosch, 2009. / Pre-eclampsia is one of the most common hypertensive disorders of pregnancy in South Africa. Presently, the only cure for pre-eclampsia is delivery, which brings with it, additional complications. As an alternative, clinical management of this disorder relies on timely diagnosis. The predictive biomarker, Placental Protein 13 (PP13), is currently used for the early diagnosis of pre-eclampsia, in an ELISA-based diagnostic kit, developed by Diagnostic Technologies Limited (DTL)1. A decrease in serum PP13 levels has been reported during the first trimester of pregnancy in women who later develop pre-eclampsia. The function of PP13 has not been fully elucidated and it is also not known whether the reduction in PP13 levels is a cause or an effect of the disease. The use of PP13 as a predictive biomarker for pre-eclampsia therefore warrants a comprehensive study of this peptide and the encoding gene, LGALS13. The aim of this study was firstly to characterise LGALS13 using a range of in silico tools. PP13 was found to be most homologous to the predicted protein product of a neighbouring “putative” gene, LOC148003. A gene conversion event between these two genes most likely underlies the so-called “hotspot mutation” in LGALS13. Data also demonstrates that the DelT mutation disrupts functionally and structurally important features of the gene and peptide sequences. Through the analysis of the putative promoter region of LGALS13, the presence of a Stimulatory protein-1 (Sp1) binding sequence element was predicted, which has implications for regulation of LGALS13. Secondly, the study aimed to establish a study cohort for the investigation of the effect that the LGALS13 genotype has on the expression of its mRNA and protein products. Serum, plasma and whole blood samples were collected and prepared from 316 pregnant women. Placental tissue samples were obtained from a selected group of these subjects for RNA extraction. Once the sampling on the two remaining targeted deliveries has occurred, the collection of samples will be batched and sent to DTL in Israel, for PP13 measurement. DNA was extracted from the whole blood samples obtained, and all study participants were genotyped for seven sequence variants within the LGALS13 gene using (i) Multiphor Single Stranded Conformational Polymorphism and Heteroduplex (SSCP/HD) analysis, (ii) restriction enzyme analysis and (iii) DNA sequencing. The genotype data sets will be compared with PP13 levels when they become available, and also with clinical parameters, once the deliveries have all occurred and the database is complete. This study demonstrated the power of an in silico approach to direct the focus of future experimental work. The newly established study cohort will be used for prospective studies aiming at a better understanding of the role which LGALS13 and PP13 play in the early prediction of preeclampsia.