Collet Dandara, Jane Sayi, Collen M.
Masimirembwa, Ayoub Magimba, Sylvia Kaaya, Klerk De Sommers, Jacques R. Snyman, Julia A. Hasler
Genetic Polymorphism of Cytochrome P450 1A1 (CYP1A1) and Glutathione Transferases (M1, T1 and P1) among Africans
The co-ordinate expression and regulation of the drug
metabolising enzymes, cytochrome P4501A1 (CYP1A1)
and glutathione transferases (GSTM1, GSTT1 and
GSTP1), and their metabolic balance in the cells of target
organs may determine whether exposure to carcinogens
results in cancer. Besides showing variability
in activity due to induction and inhibition, these enzymes
also exhibit genetic polymorphism that alter enzyme
levels and activity. We determined frequencies of
common allelic variants of CYP1A1 and glutathione
(M1, T1 and P1) among Tanzanians, South African
Venda and Zimbabweans using PCR/restriction fragment
length polymorphism techniques. The CYP1A1
Val462 mutant variant was found at a frequency of 1.3%
among 114 subjects. The GSTM1*0 genotype was
found at a frequency of 29% and 33% among Tanzanian
psychiatric patients and healthy volunteers, respectively.
Similarly, the GSTT1*0 polymorphism was present
with a frequency of 25% in both the psychiatric patients
and healthy controls. The frequency of GSTP1
Val105 variant was 16%, 12% and 21% among Tanzanians,
South African Venda and Zimbabweans, respectively.
We conclude here that CYP1A1 Val462 polymorphism
is very rare among Africans. This is the first
report of the GSTP1 Val105 variant frequency in African
populations. We show here that there are no differences
in frequencies of the variant alleles for CYP1A1,
GSTM1, GSTT1 and GSTP1 in the three African populations.
Clinical Chemical Laboratory Medicine, Walter de Gruyter
Print ISSN: 1434-6621
Volume: 40, 09/2002
Pages: 952 - 957
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