Genetic Polymorphisms are the variations found in the DNA sequences and they are
integral to the development of genetic markers to identify individuals at risk. The
genotypic distribution of various genetic polymorphisms involved in essential
hypertension (EHT) and type 2 diabetes mellitus subjects (T2DM) has been
established in many populations with conflicting results but in Malaysian subjects it
has not been well characterized. The main objective of this study was to determine
the association of various polymorphisms involved in the renin angiotensinaldosterone
system (RAAS), insulin receptor, lipoprotein lipase, interleukin gene and
G protein ß 3 subunit genes in EHT and T2DM of Malaysian subjects. This crosssectional
study includes 70 EHT without T2DM, 60 T2DM, 65 EHT with T2DM and
75 unrelated healthy control subjects. Genomic DNA was extracted from the
peripheral blood and the plasma was separated and analyzed for the biochemical
analyses. The genotypes of the various genetic polymorphisms were determined
using the polymerase chain reaction-restriction fragment length polymorphism
(PCR-RFLP), mutagenically PCR and the hot-start PCR methods. All PCR products and the restricted fragments were resolved electrophoretically on agarose and
polyacrylamide gels. Statistical analyses was done using SPPS version 14.0. The
baseline characteristics such as age, body mass index, diastolic blood pressure,
fasting plasma glucose, high density lipoprotein cholesterol and sodium differed
significantly (p<0.05) in case subjects compared to control subjects but not in low
density lipoprotein cholesterol, total cholesterol and potassium. The
insertion/deletion (I/D) and G2350A polymorphism of the angiotensin converting
enzyme (ACE) gene and the I/D polymorphism of the alpha adrenoceptor gene
differed significantly in EHT and T2DM subjects, whereas the A6G variant of the
angiotensinogen (AGT) gene differed significantly (p<0.05) in the EHT and
EHT+T2DM subjects when compared to the control subjects but not in the T2DM
subjects. However, the BglI and MboI polymorphisms of the renin gene, the A6244G
polymorphism of the insulin receptor gene, the S477X polymorphism of the
lipoprotein lipase gene, the C511T polymorphism of the interleukin gene and the
C825T polymorphism of the G protein ß 3 subunit genes did not differ significantly
(p>0.05) when compared to the control subjects. Therefore, the polymorphisms of
ACE, AGT and alpha adrenoceptor genes involved in RAAS were significantly
associated with EHT and T2DM in Malaysian subjects. The genotypes and alleles of
those polymorphisms can be considered as possible genetic markers or predisposing
risk factors for EHT and T2DM in Malaysian subjects
