Angiotensinogen gene variants in a Pakistani hypertensive population of Punjab.

BACKGROUND

The renin-angiotensin-aldosterone system (RAAS) plays a key role in blood pressure (BP) regulation. Among the components of the RAAS, the gene for the angiotensinogen (AGT) has been extensively studied. Several studies in different populations link Threonine instead of methionine at position 235 (M235T) and Methinine instead of threonine at position 174 (T174M) polymorphisms with essential hypertension. We were unable to study these polymorphisms in the Punjab population of Pakistan through routine Restriction Fragment Length Polymorphism (RFLP) method. Considering the importance of this region we decided to further investigate the 300 bp region harbouring these two single nucleotide polymorphisms.

METHODS

Samples were derived from a larger study group. Polymerase chain reaction amplified fragments were subjected to either RFLP or Single Strand Conformation Polymorphism. Single stranded DNA showing mobility shift on denaturing gel were sequenced.

RESULTS

Sequencing confirmed the presence of M235T and T174M polymorphisms in the local population. In addition to these polymorphisms one additional base was found at an identical position in two of the samples. We found a substitution of G with C just adjacent to T174M polymorphism in all seven of our samples studied.

CONCLUSIONS

We report two additional bases and one substitution in the angiotensinogen gene of Punjab population. We also suggest that SsmI can be used for the investigation of T174M polymorphism.