Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Hypertensive conditions of pregnancy, such as pre-eclampsia, are the principal direct
cause of maternal morbidity and mortality and affect up to 10% of first pregnancies
worldwide. The placenta is vital in the pathogenesis of pre-eclampsia since the
condition only occurs in the presence of placental tissue and the only cure is delivery
of the placenta and the fetus. It has been hypothesised that the placenta may be the
source of a circulating factor(s), which transports freely in the maternal system,
resulting in the multi-systemic and immunological responses that are characteristic of
pre-eclampsia. Among the potential "circulating" candidates currently being
investigated worldwide, is the tachykinin member, neurokinin B (NKB).
The aim of this project was to use a novel approach and investigate the role of
Neurokinin B in pre-eclampsia on a genetic level. This would be achieved by
bioinformatie characterisation of the neurokinin B (TAC3) and neurokinin B receptor
(TACR3) genes. Samples from thirty pre-eclampsia patients (of whom 10 also had
abruptio placentae) and twenty control individuals were used for mutation detection
analysis involving Multiphor gel electrophoresis and automated sequencing.
Three sequence variants were identified in the TAC3 gene and include: (i) 5' UTR
variant (-25 c-t); (ii) intronic variant IVS3-53 (t-g) and (iii) 3' UTR variant exon 7
(479, t-c). Only the -25 c-t variant had been reported before (SNP database). A
further two variants were identified in the TACR3 gene: (i) exon 3 variant (nt 857, a-t)
and (ii) 3' UTR variant, amplicon 5b (nt 1471, t-c), of which the latter had previously
been reported in the SNP database. In the analysis of allele and genotype frequencies,
only variant homozygosity for TAC3 -25 c-t could be associated with increased risk
of pre-eclampsia (RR 3.33, p=0.03). Follow-up work will include extended
genotyping in further stratified and larger patient cohorts and transfection studies to
assess splicing potential and functional consequences of the mutant alleles.
These data represent the first documented mutation screen of the TAC3 and TACR3
genes and report novel variants in patients with pre-eclampsia. This study contributes
to the knowledge of neurokinin B as a circulatory molecule and confirms the
heterogeneity of pre-eclampsia. / AFRIKAANSE OPSOMMING: Die belangrikste direkte oorsaak van moedersterftes is hipertensiewe toestande in
swangerskap, insluitende pre-eklampsie. Hierdie toestande kompliseer wêreldwyd
10% van alle swangerskappe. Die plasenta is kardinaal in die ontwikkeling van die
siekte aangesien dit slegs voorkom terwyl die plasenta in-situ is en die simptome
opklaar na verlossing van die plasenta. 'n Moontlike hipotese is dat die plasenta 'n
sirkulerende agens afskei wat in die moederlike sisteem beland en die uiteenlopende
multi-sistemiese simptome en tekens van die siekte veroorsaak, asook aktivering van
die immuunsisteem. Een van die moontlike kandidate wat tans wêreldwyd ondersoek
word as moontlike sirkulerende agens, is Neurokinien B (NKB), 'n lid van die
Tachikinien familie.
Die unieke benadering van hierdie projek was om die rol van Neurokinien B in pre-eklampsie
te ondersoek op 'n genetiese grondslag. Dit is bereik deur bio-informatiewe
karakterisering van die neurokinien B (TAC3) en neurokinien B reseptor (TACR3) en
deur mutasie sifting op DNA monsters van 30 pasiënte met pre-eklampsie (waarvan
10 ook abruptio placentae gehad het) en twintig kontrole individue met behulp van
Multiphor gel elektroforese en ge-outomatiseerde volgorde bepaling.
Drie volgorde variasies is geïdentifiseer in die TAC3 geen en sluit in: (i) 5' UTR
variant (-25 c-t); (ii) introniese variant IVS3-53 (t-g) en (iii) 3' UTR variant in ekson
7 (479, t-e). Slegs die -25 c-t variasie is voorheen raporteer (SNP databasis). Nog
twee variante is ook gevind in die TACR3 geen: (i) ekson 3 variant (nt 857, a-t) en (ii)
3' UTR variant, amplikon 5b (nt 1471, t-e); hierdie laaste een is al in die SNP
databasis raporteer. In 'n analise van genotipe en allele frekwensies is slegs
homosigositeit vir variant TAC3 -25 c-t geassosieër met 'n verhoogde risiko vir preeklampsie
(RR 3.33, p=0.03). Verdere werk sal nou fokus op die genotipering van
groter en gestratifiseerde pasiënt kohorte en transfeksie studies om splitsing potensiaal
en funksionele gevolge van mutante allele te ondersoek.
Hierdie data is die eerste gedokumenteerde mutasie sifting van die TAC3 en TACR3
gene en verslag word gelewer van unieke variasies in pasiënte met pre-eklampsie.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/50029 |
| Date | 12 1900 |
| Creators | Carelse Tofa, Kashefa |
| Contributors | Hillermann, R., Gebhardt, G. S., Stellenbosch University. Faculty of Medicine & Health Sciences. Dept. of Biomedical Sciences. Molecular Biology and Human Genetics. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 96 p. : ill. |
| Rights | Stellenbosch University |
Page generated in 0.0027 seconds