Search

What is already known about this subject • Genetic variability of the FcγRIIIa 176 F/V polymorphism has been widely studied in patients with systemic lupus erythomatosus and rheumatoid arthritis, as well as the general population of various White groups. • Its implications in disease pathogenesis and response to therapeutics have been well documented. • This study aimed to profile its polymorphism pattern in the Asian population, thus it serves as useful reference controls in disease association studies and tailoring therapy to ethnic-specific populations. What this study adds • In this study, we have established the genetic variability profile of the FcγRIIIa 176 F/V polymorphism in three distinct Asian groups (Chinese, Malays and Indians) and also supplemented existing data based on ethnic-specific healthy controls. • The polymorphism pattern of Malays was found to differ significantly from Chinese and Indians, which was also extended to almost all other healthy controls of various ethnic groups published elsewhere. • Such differences could have implications in disease susceptibility and pathogenesis, as well as response to drug therapeutics. Aims To determine and compare the distribution of the FcγRIIIa 176 F/V polymorphism across three ethnically distinct populations (Chinese, Asian Indians and Malays) in Singapore. Methods The FcγRIIIa 176 F/V polymorphism was genotyped by direct sequencing from genomic DNA samples obtained from normal healthy Chinese, Asian Indians and Malays (n = 192 from each population). Results The allelic frequencies of the high binding affinity FcγRIIIa 176 V allele for Chinese, Asian Indians and Malays were 35%, 33% and 46%, respectively (F allele frequencies were 65%, 67% and 54%, respectively). Genotype distributions were found to conform to the Hardy–Weinberg law (P > 0.05) in each group. χ2 comparisons revealed significant differences in the genotype distributions of the FcγRIIIa 176 V/F polymorphism of Malays from the other two populations (Chinese and Asian Indians). However, no significant difference in the genotype distributions of the FcγRIIIa 176 V/F polymorphism was observed between Chinese and Asian Indian populations. Conclusions The genotype distributions of the FcγRIIIa 176 V/F polymorphism in healthy Malays are significantly different from both Chinese and Indians. These observations provide the fundamentals on which future disease associations may be built and also present important implications for the design of therapeutic regimens amongst various ethnic groups.

This study describes the use of an acrylic acid containing random copolymer (polyethylene-co-acrylic acid, PEAA) as quartz crystal microbalance (QCM) coatings for electrode shielding and covalent tethering of DNA oligonucleotides. Commercially available silver-coated QCM was used as reaction carriers, onto which PEAA was coated to protect the electrode from undesirable effects of oxidation. AFM and SEM/EDX were used to analyze the topology and coverage of the polymer coatings. Carbodiimide chemistry was applied to attach a 17-mer single-stranded DNA probe with a C12-alkylamino tail on the 5‘-end. Seventy-mer single-stranded DNA (ss-DNA) fragments containing complementary or noncomplementary sequences were hybridized to the end-attached probes. With the use of a high stringency hybridization buffer (2 × SSC with 2% SDS), the QCM-based DNA sensor was able to detect and differentiate single-base mismatches in the 70-mer DNA target sequence. The response to the single-base mismatches near the 5‘ end or at the...

The human concentrative nucleoside transporter (hCNT2), also known as SLC28A2, plays an important role in the cellular uptake across intestinal membrane of some naturally occurring nucleosides and nucleoside analogs. This study aims to determine the genetic variability of hCNT2 (SLC28A2) in three major Asian ethnic groups residing in Singapore: Chinese, Malay and Indian, and functionally characterize the variants of hCNT2. Healthy participants (n=96) from each group were screened for genetic variations in the exons of hCNT2 (SLC28A2) using denaturing high performance liquid chromatography and sequencing analyses. A total of 23 polymorphisms were identified in the exonic and flanking intronic regions, and ethnic differences in single nucleotide polymorphism frequencies were evident. Five novel nonsynonymous variants (L12R, R142H, E172D, E385K, M612T) were constructed by mutagenesis and functionally characterized in U-251 cells. Expression of these variants in U-251 cells revealed that all except E385K can uptake various substrates of hCNT2: inosine, ribavirin and uridine.