Syndactyly is a condition in which one or more fingers or toes are born joined together. This can be caused by genetic and inherited factors that affect fetal development during pregnancy.
Syndactyly may be diagnosed during pregnancy with an ultrasound or only identified after the baby is born. When it is detected during pregnancy, the OB-GYN may recommend genetic testing to check whether the baby has an associated syndrome.
Syndactyly is classified based on how many digits are joined, where the fusion occurs, and whether the connection involves bone or only soft tissue. The most appropriate treatment is surgery, which is determined according to the type of syndactyly and the child’s age.
Possible causes
Syndactyly is mainly caused by genetic changes passed from parents to children, which affect the development of the hands or feet between the sixth and seventh weeks of pregnancy.
In some cases, this condition may be a sign of a genetic syndrome, such as Poland syndrome, Apert syndrome, or Holt-Oram syndrome, which may also be identified during pregnancy.
Syndactyly can also appear without a clear explanation. According to the NIH Genetic and Rare Diseases Information Center (GARD), genetic mutations linked to syndactyly may be inherited from parents or may occur randomly during cell division.
However, people with lighter skin are more likely to have children with this condition, and boys are more likely to develop this mutation than girls.
Confirming a diagnosis
In most cases, syndactyly is diagnosed when the baby is born, although it can also be detected during prenatal care after the second month of pregnancy through an ultrasound. If the OB-GYN sees signs of syndactyly on the ultrasound, they may request genetic testing to check for associated syndromes.
If syndactyly is diagnosed after birth, the pediatrician may recommend an X-ray to evaluate how many digits are joined and whether the bones are fused. If a genetic syndrome is identified, the doctor will also perform a detailed physical exam to check for other deformities in the baby’s body.
Different types
Syndactyly can be classified into different types depending on which digits are joined and how severe the fusion is:
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Incomplete: when the fusion does not extend to the tips of the digits.
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Complete: when the fusion extends to the tips of the digits.
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Simple: when the digits are joined only by skin.
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Complex: when the bones of the digits are also fused.
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Complicated: when the condition is caused by genetic syndromes and includes bone deformities.
There is also a very rare form of syndactyly called acrosyndactyly, or fenestrated syndactyly, which occurs when there is an opening in the fused skin between the fingers or toes. This condition can affect finger movement, especially when several fingers are involved or the fusion is extensive.
Treatment options
Treatment for syndactyly is usually planned by the pediatrician together with an orthopedic specialist, depending on the type and severity of the condition. In most cases, treatment involves surgery to separate the digits, which is typically performed after the baby is 6 months old.
However, if the fusion is severe and affects the bones, the doctor may recommend surgery before 6 months of age. The timing of treatment is based on the type of syndactyly and the child’s needs.
After surgery, the doctor will recommend using a splint to reduce movement in the hand or foot that was operated on. This helps with healing and prevents the stitches from coming loose.
After 1 month, the doctor may also recommend physical therapy exercises to help improve stiffness and swelling in the operated digit. Follow-up appointments will also be needed later to evaluate the results of the surgery.
However, if signs such as itching, redness, bleeding, or fever appear, it is important to seek medical care right away. These symptoms may be a sign of an infection at the surgical site.