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Title: Biosocial and clinical studies in twinning in an African and a Caucasian population
Author: Nylander, P. P. S.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1975
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These studies deal with various aspects of Twinning in Nigeria and Aberdeen. Zygosity of individual twin pairs was determined (a) at birth in Western Nigeria, by sex, placentation and genetic markers and (b) in 1-15 year old twins in Aberdeen by sex, blood groups, finger printing and general appearance. Only 5% of twins had monochorionic placentation in Western Nigeria (compared with 20% in Caucasian populations). All twins with monochorionic placentae were found to be 'monozygotic' apart from an unusual pair of heterosexual twins which were later shown to be chimeras. Twins with dichorionic placentae were either monozygotic or dizygotic. Other aspects of placentation and zygosity in Nigerian and Caucasian populations have been discused. The twinning incidence in Western Nigeria (48/1000 maternities) was four times that in Aberdeen - due to a high dizygotic twinning rate in Nigeria, the monozygotic rate being 4/1000 maternities as in other populations. Twinning rates were found to be influenced by maternal age, parity and height in both populations but not significantly by maternal blood groups or seasons of the year. There was an association of twinning with social class in Nigeria and with illegitimacy in Aberdeen. Serum gonadotrophin studies in both populations were suggestive that FSH levels were associated with twinning in Nigeria but not in Aberdeen and that high FSH levels found in Nigerians could be due to environmental factors. A study of inheritance in dizygotic twinning in Nigeria was also suggestive that important environmental factors could be masking the effects of genetic factors. In both populations, some obstetric complications (hydramnios and toxaemia) occurred more commonly in twin than in singleton pregnancy and their incidence appeared to be unrelated to zygosity. The association of anaemia with twin pregnancy was doubtful. The perinatal mortality was considerably higher in twins (particularly monozygotic ones) than in singletons. The effect of this higher mortality in Nigeria has been discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available