β-Thalassemia (β90 GAG→TAG): Genetic Diagnosis by Allele-Specific Polymerase Chain Reaction and Estimation of Mutant mRNA Expression by Reverse Transcription Polymerase Chain Reaction

Genetic diagnosis of a family of β-thalassemia (β90 GAG→TAG) was carried out by allelespecific polymerase chain reaction (AS-PCR). The proband, her daughter and granddaughter were proved to be heterozygotes of normal and mutant alleles. As some nonsense mutations express a decreased amount of mRNAs, we determined the expression level of the mutant mRNA of (β-thalassemia (β90 GAG→TAG), by application of a combination method of reverse transcription PCR (RT-PCR) and dot-blot hybridization with allele-specific oligonucleotides. The mutant mRNA was not markedly reduced. In conclusion, 1) individuals with the mutant β-globin gene were diagnosed successfully by AS-PCR, and 2) a significant amount of the mutant β-globin mRNA was synthesized.(Internal Medicine 35: 463-467, 1996)