Analysis of mRNA from red cells of patients with thalassemia and hemoglobin variants.

During the past decade new procedures have been developed for the isolation of RNA from a few mL of freshly collected blood. This material is reverse transcribed and the resulting cDNA can be used for the determination of the ratios between different types of globin mRNA, namely alpha 2/alpha 1, alpha/zeta, alpha/beta, gamma/beta, beta A/beta X, delta beta Lep/beta, and G gamma/A gamma. Details about these polymerase chain reaction-based methods are reviewed, and information about their usefulness in studying alpha-thalassemia, beta-thalassemia, sickle cell anemia and other beta-globin gene abnormalities, Hb Lepore heterozygosity, and heterozygosity for alpha 2- or alpha 1-globin gene mutations will be provided. The methods are also most useful in characterizing the mRNA types in single, in vitro cultured, BFU-E colonies; in colonies derived from cells of a Hb S heterozygote; for instance, the beta A- and beta(S)-mRNAs were present in all colonies and in about equal quantities, while many of those cells from a subject with a somatic cell mutant (Hb Costa Rica) contained beta A-mRNA and no beta-Costa Rica mRNA, and only a few had both types. The techniques described have considerable diagnostic value and offer a rather simple approach to the study of some of the listed diseases.