Sasitorn Bejrachandra

HLA-A, -B, -DRB1, -DQA1, and -DQB1 polymorphism in thais

In this study we examined HLA-A, -B, -DRB1, -DQA1, and -DQB1, gene allele, and haplotype frequencies in two ethnic Thai populations. We compared these frequencies to the known HLA class I and II allele profiles of non-Thai mainland and insular Southeast (SE) Asians. HLA-A locus gene and allele frequencies, are comparatively homogeneous in both Thai and non-Thai SE Asians. In contrast, HLA-B; -DRB1, -DQA1, and -DQB1 gene and allele frequencies, show more ethnic and geographic variation in SE Asians. Conserved haplotypes, or combinations of linked HLA class I and II alleles were detected in Thais, but at relatively low frequencies. It would appear that ethnic Thais, reflect an admixture of peoples from both the northern mainland and southern island groups of SE Asia.

Anion exchanger 1 mutations associated with distal renal tubular acidosis in the Thai population

AbstractWe have previously demonstrated that compound heterozygous (SAO/G701D) and homozygous (G701D/G701D) mutations of the anion exchanger 1 (AE1) gene, encoding erythroid and kidney AE1 proteins, cause autosomal recessive distal renal tubular acidosis (AR dRTA) in Thai patients. It is thus of interest to examine the prevalence of these mutations in the Thai population. The SAO and G701D mutations were examined in 844 individuals from north, northeast, central, and south Thailand. Other reported mutations including R602H, ΔV850, and A858D were also examined in some groups of subjects. The SAO mutation was common in the southern Thai population; its heterozygote frequency was 7/206 and estimated allele frequency 1.70%. However, this mutation was not observed in populations of three other regions of Thailand. In contrast, the G701D mutation was not found in the southern population but was observed in the northern, northeastern, and central populations, with heterozygote frequencies of 1/216, 3/205, and 1/217, and estimated allele frequencies of 0.23%, 0.73%, and 0.23%, respectively. The higher allele frequency of the G701D mutation in the northeastern Thai population corresponds to our previous finding that all Thai patients with AR dRTA attributable to homozygous G701D mutation originate from this population. This suggests that the G701D allele that is observed in this region might arise in northeastern Thailand. The presence of patients with compound heterozygous SAO/G701D in southern Thailand and Malaysia and their apparently absence in northeastern Thailand indicate that the G701D allele may have migrated to the southern peninsular region where SAO is common, resulting in pathogenic allelic interaction.

HLA-DPB1 polymorphism in the Thais of Southeast Asia

In this study we examined DPB1 allele frequencies in five ethnic Thai populations resident in different regions of Thailand and neighboring countries. In contrast to other Asian and Pacific populations such as the Japanese, Chinese, Korean, and Papua New Guineans, where DPB1*0501 has consistently been shown to be the most frequent allele, NE Thais and Thai-Khmers demonstrate a prevalence of DPB1*1301. Comparison of DPB1 allele frequencies in the Thais of SE Asia, with known frequencies in the Chinese and Japanese populations of E Asia, would appear to confirm previous calculations of genetic divergence between these Oriental populations.

Red Cell Genotyping by Multiplex PCR Identifies Antigen-Matched Blood Units for Transfusion-Dependent Thai Patients

Background: Antigen-negative red cell transfusion is required for transfusion-dependent patients. We developed multiplex PCR for red cell genotyping and calculated the possibility of finding compatible predicted phenotypes in Thai blood donor populations according to red cell alloantibodies found among Thai patients. Methods: 600 DNA samples obtained from unrelated healthy central and northern Thai blood donors were tested with the newly developed multiplex PCR for FY*A, FY*B, JK*A, JK*B, RHCE*e, RHCE*E, DI*A and GYP*Hut, GYP*Mur, GYP*Hop, GYP*Bun, and GYP*HF allele detections. Additionally, the possibility of finding compatible predicted phenotypes in two Thai blood donor populations was calculated to estimate the minimal number of tests needed to provide compatible blood. Results: The validity of multiplex PCR using known DNA controls and the phenotyping and genotyping results obtained by serological and PCR-SSP techniques were in agreement. The possibility of finding at least one compatible blood unit for patients with multiple antibodies was comparable in Thai populations. Conclusions: The multiplex PCR for red cell genotyping simultaneously interprets 7 alleles and 1 hybrid GP group. Similar strategies can be applied in other populations depending on alloantibody frequencies in transfusion-dependent patients, especially in a country with limited resources.

Improved Allele‐Specific PCR Technique for Kidd Blood Group Genotyping

We developed an allele‐specific polymerase chain reaction (AS‐PCR) technique for Kidd blood group genotyping. J. Clin. Lab. Anal. 27:53–58, 2013.