Polydactyly is the most common hereditary limb malformation in clinical practice. It can appear

as an isolated disease or as part of a complex syndrome. This paper summarizes and updates the classification

and phenotype of independent polydactyly, the cellular molecular basis of their development, the key

signaling pathways that regulate polydactyly and related genes (SHH-GLI3 pathway and the Hox family). We

believe that this information has very important clinical value. On the other hand, it can also help researchers

understand the molecular basis of forming polydactyly more deeply, and will contribute to more systematic

genetic studies in the future.