A second, elongated, alpha 2-globin mRNA is present in reticulocytes from normal persons and subjects with terminating codon or poly A mutations.

With an RT-PCR procedure we have identified a second, elongated, alpha 2-globin mRNA in reticulocytes of normal persons and of patients with alpha-thal, particularly those with mutations in the terminating codon (TAA-->CAA; Hb Constant Spring; TAA-->TAT, Hb Paksé) or in the poly A site (AATAAA-->AATAAG). This type of mRNA is elongated because a result a cryptic poly A site 1048 bp past the terminating codon is used. Even some 5% of the alpha 2-mRNA of normal persons is of the elongated type. Quantitative data suggest high levels of this mRNA in heterozygous and homozygous carriers of poly A mutations and low levels in patients with the terminating codon mutations. Hematological and Hb data suggest that translation of these elongated mRNAs is minimal. No elongated alpha 1-mRNA has been observed.