A simple DNA diagnostic method for human genetic disorders.

A fast, reliable, and simple technique for detecting point mutations in unfractionated human DNA has been developed. Oligonucleotide probes complementary to either sickle- or normal beta-globin DNA are labeled by primer extension and hybridized to DNA applied to nitrocellulose paper in a dot-blot format. A short hybridization time (about 1 h) and low probe concentration (about 1 nM) yield low background and high specificity. Double-blind trials show 100% agreement with restriction fragment length polymorphism (RFLP) analysis of DNA from normal, sickle, and heterozygous subjects.