Polydactyly with six fingers is one of the most common hand congenital malformations in China, and it is a genetic related disease, especially when it grows next to the thumb. Among them, polydactyly is the most common. Six fingers syndrome is a sex chromosome dominant genetic disease, and the pathogenic gene is located on the X chromosome. If the patient is male, the probability of illness with the offspring of normal women is 50% (the boy is normal and the girl is a patient with six fingers). If the patient is female, it can be divided into complete dominance and incomplete dominance. The probability of children born with complete dominance is 100%, and the probability of children born with incomplete dominance and normal males is 50% (the probability of boys and girls getting sick is the same). Therefore, the hereditary probability of hexadactyly is very high, and it is accompanied by heredity. Therefore, if close relatives get married, the probability of suffering from this disease will increase.