Webbed toes, medically known as syndactyly, describe a condition where two or more toes are fused. This fusion can involve skin and soft tissues, or extend to bones, nerves, and blood vessels. Syndactyly is a congenital difference, meaning it is present at birth. It affects approximately 1 in 2,000 to 3,000 newborns and typically does not cause significant functional issues.
How Toes Form
The development of distinct fingers and toes occurs during early fetal development. Around the sixth to eighth week of pregnancy, a baby’s hands and feet initially form as paddle-like structures with webbing between what will become the individual digits, similar to a duck’s foot.
For separate digits to form, a programmed process of cell death, called apoptosis, must occur. Apoptosis eliminates the tissue in these interdigital spaces, effectively “sculpting” the individual fingers and toes. When this process is incomplete or disrupted, the cells in the webbing between the toes do not fully recede, leading to the fusion of digits. This fusion can involve only skin and soft tissues (simple syndactyly) or be more extensive, involving bones and other structures (complex syndactyly).
Genetic Influences
Webbed toes are often an inherited trait. A family history of syndactyly increases the likelihood of it appearing in subsequent generations. In some cases, webbed toes follow an autosomal dominant inheritance pattern, meaning only one copy of an altered gene from a parent is sufficient for the condition to manifest.
Even when inherited, the gene’s expression can vary, leading to different degrees of webbing within the same family. While specific gene mutations are sometimes identified, the exact genetic cause remains unknown in other instances. Approximately 10% to 40% of individuals with syndactyly have a family history of the condition, even when it is not part of a larger syndrome.
When Webbing is Part of a Syndrome
Beyond isolated occurrences, webbed toes can also be a feature of various genetic syndromes. In these instances, syndactyly is not a standalone characteristic but one of several physical or developmental features associated with a broader genetic condition. For example, Apert syndrome is a rare genetic disorder characterized by fusion of skull bones, craniofacial anomalies, and severe syndactyly of both hands and feet. In Apert syndrome, the fusion can be extensive, sometimes involving all fingers and toes.
Poland syndrome is another condition where syndactyly is present. Individuals with Poland syndrome have missing or underdeveloped muscles on one side of the body, most commonly the chest muscles, along with hand abnormalities that can include webbed fingers. While its exact genetic basis is not fully understood, it affects one side of the body and can involve simple syndactyly. More than 28 syndromes include syndactyly as a shared feature.
Life with Webbed Toes
For many individuals, webbed toes do not cause functional problems or impact daily activities like walking, running, or swimming. Simple syndactyly, where only skin and soft tissue are fused, has minimal impact on mobility. However, in cases of more severe or complex webbing involving bones or uneven digit lengths, movement may be limited, potentially affecting balance or causing discomfort with certain footwear.
Surgical separation is a treatment option for webbed toes, performed in early childhood, usually between 6 months and 2 years of age. The decision for surgery depends on whether the webbing causes functional impairment or if it is a cosmetic concern. While surgery for webbed fingers is recommended to improve hand function, separating webbed toes is typically done for cosmetic reasons, as untreated webbed toes do not cause significant problems. The outlook after surgery is positive, with good functional outcomes.