Hemoglobin Köln: direct analysis of the gene mutation by synthetic DNA probes.

The molecular defect leading to Hb Köln has been analyzed by synthetic oligonucleotides. Thus, DNA of 19 nucleotides, in length corresponding to the normal and mutant beta-globin gene sequences, were used to develop a direct assay for the beta k-gene that codes for this most common form of the unstable hemoglobins. The use of synthetic oligonucleotides established that the Hb Köln mutation is due to a G-to-A transition. The conditions described here should result in the determination of all Hb Köln genotypes with a high level of confidence.