Congenital Hand Differences

A congenital hand deformity is a change, or difference, in the typical way your baby’s hand or hands form. More often called a congenital hand difference, most aren’t preventable and many can’t be detected before birth. There are several different types of variations and many different treatment options available.


What is a congenital hand difference?

A congenital hand difference, or congenital hand deformity, is a variation in the typical formation of your child’s hand. Congenital means “present at birth.”

Differences in your child’s physical appearance — such as hand differences — are noticeable at birth and can be distressing. In some cases, feelings of anger and guilt develop. You may blame yourself for some “failure” during your pregnancy. Parents may also become angry with their healthcare providers for not detecting the problem during routine prenatal care.

In fact, no one is at fault. Most hand differences aren’t hereditary (don’t run in families). They aren’t preventable, and many can’t be detected before birth.

Types of congenital hand differences

Congenital hand differences can be grouped based on the type of deformity. These general categories include:

  • Issues with the formation of the entire arm or hand.
  • Inability of parts of the hand to separate.
  • Extra fingers or thumb.
  • Undergrowth or overgrowth of the hand, fingers and/or thumb.

Specific types of congenital hand differences include syndactyly, polydactyly, radial club hand and cleft hand.


Syndactyly is the most common congenital hand difference. The word syndactyly comes from the Greek words syn, which means “together,” and daktylos, which means “digit” (finger or toe).

Syndactyly means your child’s fingers are fused together or the webbing between their fingers extends farther up their fingers than what’s typical. Sometimes, the condition can be simple, with only skin shared by their fingers. Sometimes the condition is complex, with shared bone, nerves, blood vessels and/or other tissues.


Polydactyly means your child has more than five digits (poly means “many”). Sometimes their extra finger or thumb may be attached only by skin or nerves. Sometimes it may have normal parts and be attached to a joint or an extra bone in their hand.

There are two main types of polydactyly:

  • Ulnar polydactyly: Ulnar polydactyly is the more common type of polydactyly. Ulnar polydactyly means an extra finger or part of a finger develops on or near the little finger of your child’s hand. Ulnar refers to the ulna, the larger of the two bones of the forearm. The ulna is on the same side of the arm as the little finger.
  • Radial polydactyly: Radial polydactyly may also be called thumb polydactyly. Radial (thumb) polydactyly means there are multiple thumbs on one hand.
Radial club hand

Radial club hand means the radial — or thumb-side — of the arm is malformed. (Radial refers to radius, the smaller bone of the forearm.) This causes the forearm to shorten and curve, giving the appearance of a J-shaped club. The thumb may be small or completely missing.

With a shortened forearm, people with radial club hand may have difficulty performing tasks that require two hands. This difference can occur in one (unilateral) or both (bilateral) arms.

Cleft hand

Cleft hand refers to a group of congenital hand differences. The fingers or parts of fingers in the center of your child’s hand are missing. This leaves a V-shaped space or indentation called a cleft. Other hand differences, particularly syndactyly and polydactyly, often occur at the same time. There are many types of cleft hand.

Typically, a person with cleft hand will have a gap in the palm and their middle finger or fingers will be missing. Cleft hand can occur in one or both arms. (Some people have a family history of clefts in both hands and feet.) In typical cleft hand, the hand is almost normal in size, and the arm bones are usually normal.

How common are congenital hand differences?

About 2 out of 1,000 newborns will be born with a congenital hand difference. The condition is more common in babies assigned male at birth (AMAB) than babies assigned female at birth (AFAB).


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Symptoms and Causes

What causes congenital hand differences?

A fetus’s arms and hands form between the fourth and sixth week of pregnancy. Any disruption of this process can lead to a congenital hand difference. There are many factors that can affect the development of the human hand. These are generally divided into genetic factors and environmental factors.

Genetic factors

Genetic factors play a role in hand and arm formation. Genes contain instructions for the growth and function of each cell in the body. They’re passed on to children from their parents but can also change (mutate) on their own.

In the case of hand differences, the genetic changes generally occur for no apparent reason. Less common are changes that run in families.

Environmental factors

Environmental factors include infections and the use of certain drugs. These drugs include thalidomide (a drug used to treat nausea) and some drugs used for chemotherapy. Environmental factors may cause a breakdown in otherwise healthy tissue. The breakdown can alter the developmental process and lead to a difference in hand formation.

Some hand differences can be explained by these factors. Others have no known cause. In some cases, the hand difference is an isolated event. In other cases, the difference is part of a syndrome that affects multiple parts of the body.

What are the complications of congenital hand differences?

Depending on the type and severity of your child’s hand difference, they may have no trouble adapting and functioning. However, other children will experience issues without treatment. Complications of congenital hand differences may include:

  • Developmental delays.
  • Trouble with basic self-care and daily living activities.
  • Limitations on certain sports and other activities.
  • Emotional and social issues.


Diagnosis and Tests

How are congenital hand differences diagnosed?

Congenital hand differences are generally noticed at birth. However, your child’s healthcare provider may want to take X-rays. The X-rays can help determine the extent of the bone and tissue involvement. Your child’s provider will be able to tell if your child’s hand difference is simple or complex.

Management and Treatment

What are the benefits of treatment for hand differences?

Each child with a hand difference is unique. The approach to treatment is based on your child’s individual needs. The main goal and benefit of treatment is to improve your child’s ability to function with the hand difference. Another aim is to improve the appearance of their hand and support your child’s self-esteem.


What are the common treatment options for hand deformities?

Options for treating hand differences include:

Syndactyly is usually treated by surgically separating the fingers. Skin grafts are often necessary, as more skin may be needed to provide coverage for the two fingers. A provider may also recommend casting or splinting, as well as physical therapy, especially in complex cases. These treatment options will help maximize your child’s hand function after surgery.

Polydactyly can be treated by surgically removing the extra finger or thumb and reconstructing the remaining finger or thumb.

Treatment of radial club hand depends on the functional abilities and needs of your child. The treatment may include limb manipulation and stretching, splinting or casting, and/or surgery.

Keep in mind that treatment can’t “cure” your child’s hand difference. But it can help to improve the function and appearance of your child’s hand. A positive attitude and acceptance of the difference — by you and your child — are important to treatment success and your child’s healthy development.

What are the risks of treatment for hand differences?

Risks include nerve injury, infection, bleeding and stiffness. There’s also a risk that treatment won’t restore or create a typical digit or hand.


Can congenital hand differences be prevented?

You can’t prevent congenital hand differences because they’re often the result of genetics. But taking care of yourself before and during your pregnancy can give your baby the best chance for a healthy start at life. Make sure to go to all of your prenatal care appointments, and avoid smoking and drinking during your pregnancy.

Outlook / Prognosis

What is the outlook for treatment of hand deformities?

The outlook for treatment varies with the type and complexity of your child’s hand difference. When their hand difference is an isolated occurrence, the outlook is generally good. Most children can learn to adapt to their differences. If the difference is part of a syndrome, the outlook depends on the type and extent of the condition.

Living With

How do I take care of my child?

As the parent of a child with a congenital hand difference, you want to support your child the best you can. Ask your child’s healthcare provider about resources such as support groups. Talking with people who are going through the same situation can be helpful for you and your child.

What questions should I ask my child’s healthcare provider?

You likely have many questions about your child’s condition. Examples of questions that you may want to ask your child’s provider include:

  • What type of hand difference does my child have?
  • What kind of treatment do you recommend?
  • Will my child be able to function like a typical child?
  • How can I help my child adapt to their hand difference?

A note from Cleveland Clinic

When you’re an expectant parent and you hear something unexpected about the fetus or about your infant, you may wonder what lies ahead. Most congenital hand deformities or differences can’t be prevented, but you can take some steps to reduce the likelihood of environmental effects. Remember to always discuss your concerns with your healthcare provider and follow their instructions regarding screening tests, medications, etc.

Medically Reviewed

Last reviewed on 07/05/2023.

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