Development of a Quantitative Multiplex PCR to Detect Three Common Alpha Thalassemia Deletions

Abstract

Alpha thalassemia is an autosomal recessive genetic disorder with a high prevalence in the Middle East. The severe form of alpha-thalassemia is incompatible with life and can cause significant obstetric complications in the mother. Therefore, it is important to determine the genotype in parents who have a chance of having a fetus with one of the severe forms of this disease. A total of 112 samples that were previously analyzed for common alpha thalassemia mutations in Iran were used in this study. A new multiplex PCR including quantitative polymerase chain reaction to amplify the homologous regions of the alpha-globin gene cluster and fluorescent gap PCR was designed to identify −α3.7, −α4.2, --MED deletions. The ROC curve was used to determine the optimum cutoff points. Statistical analysis showed that there is a significant difference between the peak height ratios for different genotypes. The peak corresponding to the 297 bp fragment resulting from the amplification of the allele with MED-I deletion was detected in all the samples with this deletion. Different cutoffs for a range of sensitivities and specificities were determined by the ROC curve. The suggested method can identify three common large deletions in the alpha-globin gene cluster. A study with a larger sample size can provide more accurate information about the sensitivity and specificity of this test.