Introduction: Sulfonylureas (SUs) are commonly used drugs for type 2 diabetes mellitus (T2DM) in the Philippines. This study aimed to associate genetic variants with poor response to gliclazide and glimepiride among Filipinos. Methodology: Two independent, dichotomous longitudinal substudies enrolled 139 and 113 participants in the gliclazide and glimepiride substudies, respectively. DNA from blood samples underwent customized genotyping for candidate genes using microarray. Allelic and genotypic features and clinical associations were determined using exact statistical methods. Results: Three months after sulfonylurea monotherapy, 18 (13%) were found to be poorly responsive to gliclazide, while 7 (6%) had poor response to glimepiride. Seven genetic variants were nominally associated (p<0.05) with poor gliclazide response, while three variants were nominally associated with poor glimepiride response. For gliclazide response, carboxypeptidase-associated variants (rs319952 and rs393994 of AGBL4 and rs2229437 of PRCP) had the highest genotypic association; other variants include rs9806699, rs7119, rs6465084 and rs1234315. For glimepiride response, 2 variants were nominally associated: CLCN6-NPPA-MTHFR gene cluster – rs5063 and rs17367504 – and rs2299267 from the PON2 loci. Conclusion Genetic variants were found to have a nominal association with sulfonylurea response among Filipinos. These findings can guide for future study directions on pharmacotherapeutic applications for sulfonylurea treatment in this population.
genetic variants ; sulfonylureas ; Filipino ; gliclazide

Objective. Several studies showed that genetic factors affect responsiveness to statins among different populations. This study investigated the associations of candidate genetic variants with poor response to statins among Filipinos.

Methods. In this unmatched case-control study, dyslipidemic participants were grouped into statin responders and poor responders based on the degree of reduction in LDL-c from baseline. DNA from blood samples were genotyped and analyzed. The association of candidate variants with statin response was determined using chi-square and logistic regression analysis.

Results. We included 162 adults on statins (30 poor responders as cases, 132 good responders as controls). The following variants are nominally associated with poor response to statin among Filipinos at a per-comparison error rate of 0.05: rs173539 near CETP (OR=3.05, p=0.015), rs1800591 in MTTP (OR=3.07, p=0.021), and rs1558861 near the BUD13-ZPR1-APOA5 region (OR=5.08, p=0.004).

Conclusion. Genetic variants near CETP, MTTP and the BUD13-ZPR1-APOA5 region are associated with poor response to statins among Filipinos. Further study is recommended to test the external validity of the study in the general Filipino population.

Lipids ; Hydroxymethylglutaryl-CoA Reductase Inhibitors

Background. Low levels of high-density lipoprotein cholesterol (HDL-c) is a well-recognized risk factor in the development of cardiovascular diseases. Associated gene variants for low HDL-c have already been demonstrated in various populations. Such associations have yet to be established among Filipinos who reportedly have a much higher prevalence of low HDL-c levels compared to other races.

Objective. To determine the association of selected genetic variants and clinical factors with low HDL-c phenotype in Filipinos.

Methods. An age- and sex-matched case-control study was conducted among adult Filipino participants with serum HDL-c concentration less than 35 mg/dL (n=61) and those with HDL-c levels of more than 40 mg/dL (n=116). Genotyping was done using DNA obtained from blood samples. Candidate variants were correlated with the low HDL-c phenotype using chi-squared test and conditional logistic regression analysis.

Results. Twelve single nucleotide polymorphisms (SNPs) were associated with low HDL-c phenotype among Filipinos with univariate regression analysis. The variant rs1260326 of glucokinase regulator (GCKR) (CT genotype: adjusted OR=5.17; p-value=0.007; TT genotype: adjusted OR=6.28; p-value=0.027) remained associated with low HDL-c phenotype, together with hypertension and elevated body mass index, after multiple regression analysis.

Conclusion. The variant rs1260326 near GCKR is associated with low HDL-c phenotype among Filipinos. Its role in the expression of low HDL-c phenotype should be further investigated prior to the development of possible clinical applications.

Cardiovascular Diseases ; Dyslipidemias ; Genetics ; Polymorphism, Single Nucleotide