SCD and Schnyder corneal dystrophy: SCD mutation correction is an effective strategy for preclinical studies of SCD using gene editing technology, which is divided into two methods: one is to directly repair the mutated SCD codon (valine) to the normal codon (glutamate), and the other is to convert the mutated SCD codon to the benign nonsickle G‐Makassar variant (alanine; Figure 4B).218