What is single-base editing?

Single-base editing is a new gene-editing technique that converts one base into another. Old techniques have only been able to take advantage of complementary base pairing and change a G-C pair into an A-T pair, but this new method changes adenine into inosine, which reads as guanine. So, the cell identifies this as a mistake and slots in a cytosine where the thymine was. This A-T to G-C base edit could reverse mutations from G-C to A-T and treat hereditary hemochromatosis as well as sickle-cell anemia. 

Resource: https://www.wired.com/story/new-science-could-sharpen-crisprs-gene-editing-scalpel/