Polydactyly and syndactyly are conditions that occur in the developing fetus. Most often these conditions are caused by genetic factors. Both polydactyly and syndactyly can be caused by the presence of an autosomal dominant trait. An autosomal dominant trait is a gene that is not related to the chromosome that determines gender; therefore, it affects boys and girls equally. Because the gene is dominant, when one parent has the gene, each of his or her children has a 50 percent chance of having polydactyly or syndactyly.
The primary symptom of polydactyly is the presence of extra digits on the hands or feet. Polydactyly rarely causes any difficulties for the child. The extra fingers and/or toes are usually removed for cosmetic reasons. In children with syndactyly of the hand, finger function may be impaired and, in cases where fingers of different lengths are connected by tissue, finger growth may be limited unless surgery to separate the fingers is performed.
Diagnosis is made during the initial physical examination at birth. Some children with polydactyly will need radiographs or x rays to determine if there is bone present in the extra digit. This will indicate what type of surgery is necessary to remove the extra finger or toe. When polydactyly is more severe and involves digits with bone, a pediatric orthopedic surgeon will perform the repair. In children with syndactyly, the surgeon must determine if the fusion involves muscle tissue and blood vessels, and in children with severe polydactyly of the fingers, a surgeon specializing in hands may evaluate the child as well. Some children with syndactyly may also have cardiac or heart problems; therefore, an electrocardiogram (EKG) may be ordered to evaluate heart function.
Deborah L. Nurmi MS, Thomson Gale, Gale, Detroit,