Prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand.

Background & objectives: Alpha-thalassaemias are genetic disorders with high prevalence in northern Thailand. However, common genotypes and current data on the prevalence of α-thalassaemias have not been reported in this region. Therefore, the objective of the present study was to determine the prevalence of α-thalassaemia genotypes in pregnant women in northern Thailand. Methods: Genomic DNA was extracted from blood samples of pregnant women who came to Maharaj Nakorn Chiang Mai University Hospital during July 2009 to 2010. The common deletion and point mutation genotypes of α-thalassaemia were evaluated by gap- polymerase chain reaction (PCR) and PCR with restriction fragment length polymorphism (RFLP). Results: Genotypes of 638 pregnant women were: 409 samples (64.11%) being normal subjects (αα/αα) and 229 samples (35.89%) with α-thalassaemias. These 229 samples could be classified into deletional HbH disease (--SEA/-α3.7) for 18 samples (2.82%); heterozygous α0-thalassaemia --SEA type (--SEA/αα)) for 78 (12.23%); heterozygous α+-thalassaemia - α3.7 type (-α3.7/αα) for 99 (15.52%); homozygous α+-thalassaemia - α3.7 type (-α3.7/- α3.7) for five (0.78%); heterozygous α+-thalassaemia - α4.2 type (-α4.2/αα) for two (0.31%); and heterozygous HbCS (αCSα/αα) for 27 (4.23%) cases. Interpretation & conclusions: The prevalence of α-thalassaemias in pregnant women in northern Thailand was high. This finding supports the implementation of the prevention and control of this common genetic disorder by screening for α-thalassaemia genotypes.

Frequencies of IL10 SNP genotypes by multiplex PCR-SSP and their association with viral load and CD4 counts in HIV-1-infected Thais.

Background: Interleukin (IL)-10 is an immuno-regulatory cytokine, levels of which can be influenced by single nucleotide polymorphisms (SNPs) in the promoter. Some, but not all previous studies have shown associations of IL10 SNPs with HIV-1 disease progression, using markers such as viral load or CD4 count. There are few data on IL10 SNP frequencies and HIV-1 disease in regions where non-B HIV-1 subtypes predominate. Objective: To determine genotypes, haplotypes, allele frequencies and associations with markers of HIV-1 disease progression of IL10 SNPs. Methods: A new multiplexed PCR-SSP assay to detect IL10 SNPs at positions -1082, -819 and -592 was developed and used to determine genotypes and haplotypes in 244 HIV-1 CRF01_AE-infected northern Thais having a median time since HIV-1 infection of 2.7 years. Results: At position -1082 of IL10, AA genotype and A allele were the most common (87.3% and 93.2%, respectively). The -819 CT and -592 CA genotypes were the most prevalent (44.3%), and -819T and -592A were the most prevalent alleles (64.8%). The ATA/ATA was the most common genotype (42.6%) with the most prevalent haplotype of ATA (64.7%). No associations of any of the three IL10 SNPs with CD4+ or CD8+ T cell counts or with viral load were found. Conclusions: This first report of IL10-1082A, -819T and the IL10-592A allele frequencies in HIV-1-infected Thais shows the highest frequencies in HIV-1-infected persons worldwide. The lack of association of IL10 SNPs with CD4+ T cell count and viral load suggest that other genes may influence these markers in HIV-1-infected Thais.