Familial hypercholesterolaemia (FH) and Familial defective apolipoprotein B100 (FDB) are autosomal dominant inherited diseases of lipid metabolism caused by mutations in the low density lipoprotein (LDL) receptor and apolipoprotein B 100 genes. FH is clinically characterised by elevated concentrations of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), presence of xanthomata and premature atherosclerosis. Both conditions are associated with coronary artery disease but may be clinically indistinguishable. Seventy-two (72) FH patients were diagnosed based on the Simon Broome's criteria. Mutational screening was performed by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). Positive mutations were subjected to DNA sequencing for confirmation of the mutation. We successfully amplified all exons in the LDL receptor and apo B100 genes. DGGE was performed in all exons of the LDL receptor (except for exons 4-3', 18 and promoter region) and apo B100 genes. We have identified four different mutations in the LDL receptor gene but no mutation was detected in the apo B 100 gene. The apo B100 gene mutation was not detected on DGGE screening as sequencing was not performed for negative cases on DGGE technique. To our knowledge, the C234S mutation (exon 5) is a novel mutation worldwide. The D69N mutation (exon 3) has been reported locally while the R385W (exon 9) and R716G (exon 15) mutations have not been reported locally. However, only 4 mutations have been identified among 14/72 patients (19.4%) in 39 FH families. Specificity (1-false positive) of this technique was 44.7% based on the fact that 42/76 (55.3%) samples with band shifts showed normal DNA sequencing results. A more sensitive method needs to be addressed in future studies in order to fully characterise the LDLR and apo B100 genes such as denaturing high performance liquid chromatography. In conclusion, we have developed the DNA analysis for FH patients using PCR-DGGE technique. DNA analysis plays an important role to characterise the type of mutations and forms an adjunct to clinical diagnosis.
Diabetes mellitus is an important coronary artery disease risk factor. The presence of microalbuminuria, which indicates renal involvement in diabetic patients, is associated with an increased cardiovascular risk. There are suggestions that diabetic patients with microalbuminuria have more adverse risk profile such as higher ambulatory blood pressure and total cholesterol levels to account for the increased cardiovascular morbidity and mortality. QT dispersion is increasingly being recognized as a prognostic factor for coronary artery disease and sudden death. Some studies have suggested that QT dispersion is an important predictor of mortality in Type II diabetic patients. Our cross sectional study was to compare the QT dispersion and 24 hour ambulatory blood pressure monitoring between diabetic patients with microalbuminuria and those without microalbuminuria. Diabetic patients with overt coronary artery disease were excluded from the study. A total of 108 patients were recruited of which 57 patients had microalbuminuria and 51 were without microalbuminuria. The mean value of QT dispersion was significantly higher in patients with microalbuminuria than in patients without microalbuminuria (58.9 +/- 27.9 ms vs. 47.1 +/- 25.0 ms, p < 0.05). The mean 24 hour systolic and diastolic blood pressures were significantly higher in patients with microalbuminuria than in patients without microalbuminuria (129.5 +/- 12.3 mm Hg vs 122.3 +/- 10.2 mm Hg, p < 0.05 and 78.4 +/- 6.9 mm Hg vs 75.3 +/- 6.8 mm Hg, p < 0.05, respectively). Our study suggests that QT dispersion prolongation, related perhaps to some autonomic dysfunction, is an early manifestation of cardiovascular aberration in diabetic patients with microalbuminuria. The higher blood pressure levels recorded during a 24-hour period min diabetics with microalbuminuria could also possibly account for the worse cardiovascular outcome in this group of patients.
Diabetes mellitus is an important risk factor for the development of coronary artery disease. The presence of microalbuminuria, which indicates renal involvement in diabetic patients, influences the progression of coronary artery disease. New coronary risk factors such as C-reactive protein (CRP), Lipoprotein a [Lp (a)] and fibrinogen are increasingly being recognized as important cardiovascular prognostic factors. These new coronary risk factors could account for the worse cardiovascular prognosis in diabetic patients with microalbuminuria. Our cross sectional study was to compare the prevalence of elevated CRP and the levels of Lp (a) and fibrinogen between diabetic patients with microalbuminuria and those without microalbuminuria. Diabetic patients with overt coronary artery disease were excluded from the study. A total of 108 patients were recruited of which 57 patients had microalbuminuria and 51 were without microalbuminuria. There was no difference in the number of patients with elevated CRP between these two groups. There were also no significant differences in the mean values of Lp (a) and fibrinogen between diabetic patients with and without microalbuminuria. The inflammatory marker CRP and coagulopathy markers i.e. Lp (a) and fibrinogen seem not to be perturbed in diabetic patients with microalbuminuria.