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The polymorphism of intron 1 of the CETP gene
(B1; presence or B2; absence of a TaqIB restriction site)
was shown to be a determinant of HDL -C in nondiabetic populations.
But the gene effect appears to be modified by environmental factors.
In Netherlands, Dullaart et al (1997)16 showed that TaqIB CETP gene
polymorphism is a strong and independent determinant of HDL-C in type 1
diabetes. HDL-C level of B1B1 homozygotes patients was 0.39mmol/L lower
than B2B2 patients(P<0.01). In Finland, the exon 16 of the CETP gene
was screened for possible mutations in patients with low plasma HDL-C
and diagnosed coronary heart disease (CHD) and a single G to A substitution
at base pair 1696 was found in 3*untranslated region of the CETP gene.
The sequence difference is located 92 bp upstream from the polyadenylation
site. The mutation is associated with low CETP activity (71 nmol/h/ml vs.100
nmol/h/ml , P<0.01)and high HDL-C level (1.01 mmol/ ml vs.0.92 mmol /ml) in
homozygotes and non-mutation patients separately. As Exon 16 contains the
neutral lipid binding domain essential for transfer activity, the results
suggested that CETP gene may be important in the regulation of reverse
cholesterol transport and associated with macrovascular disease in type 2
diabetes independent of lipid levels.
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