Symbrachydactyly (Short, Joined Fingers)

Symbrachydactyly is a rare congenital hand difference. “Congenital” means the condition is present when your baby is born. If your baby has symbrachydactyly, one of their hands is smaller than the other one. The fingers on that hand are small or short. They may be missing fingers or their thumb.

The condition happens during fetal development. It’s not an inherited disorder that runs in families. Symbrachydactyly (pronounced “sim-brak-ih-DAK-tuh-lee”) causes physical differences in your child’s hand. It doesn’t affect their development as they grow up.

Symbrachydactyly types

There are four types of symbrachydactyly. The types vary based on how the condition affects your child’s hand. The types are:

• Short-finger symbrachydactyly (type 1): Your child has all or most of their thumb and fingers on the affected hand. Their fingers will be noticeably shorter than the fingers on their other hand. They may be missing bones in their fingers.
• Oligodactyly symbrachydactyly (type 2): Your child’s hand has a thumb and pinkie finger but no other fingers. Providers may refer to this as an atypical cleft hand.
• Monodactylic symbrachydactyly (type 3): Your child has a fully developed thumb on the affected hand. They may have four partially developed fingers.
• Peromelic symbrachydactyly (type 4:) Your child doesn’t have a thumb or fingers on the affected hand.

Symbrachydactyly symptoms

Your child’s symptoms may vary depending on the type of symbrachydactyly that they have. For example, your child’s forearm may be shorter than their other forearm. But all children with this condition have fingers that are shorter than usual. They often have missing fingers and thumbs.

Symbrachydactyly causes

There’s no known cause of symbrachydactyly. Some experts think it may happen during development when blood stops flowing to a fetus’s arm. Arm bones start as small buds or bumps that extend from a fetus’s body. The buds or bumps need a steady flow of blood to grow and become a fully formed arm and hand. Without blood flow, a fetus’s arm, fingers or thumb may not develop normally.

How doctors diagnose symbrachydactyly

A pediatrician will examine your baby’s hand. They’ll identify specific issues with your baby’s hand or fingers. They’ll use that information to diagnose the type of symbrachydactyly that your baby has. Your child’s pediatrician may do X-rays of your child’s hand. The X-ray results will help them plan treatment.

Your child’s pediatrician may classify your child’s condition as being mild, moderate or severe:

• Mild symbrachydactyly means your child has slightly short fingers. They may have small amounts of webbing (skin) that connects their fingers. Their hand or forearm may be shorter than their other hand or forearm.
• Moderate symbrachydactyly is when most or all the finger bones in your child’s hand are missing. Their fingers appear as small stumps. Their thumb may be shorter than usual.
• Severe symbrachydactyly means your child’s hand is missing fingers. They may have a partial thumb or no thumb.

Treatment for symbrachydactyly

The goal of symbrachydactyly treatment is to help your child use their hand as much as possible. Your child may have surgery to fix issues that make their hands look different. Other treatment options are:

• Physical therapy to strengthen your child’s arm and hand and help them move their hand more easily
• Occupational therapy to help your child learn ways to manage daily activities
• Splints to support their hand
• Protheses to replace missing fingers and thumbs

What can I expect if my child has symbrachydactyly?

This condition won’t affect your child’s overall growth and development. But having symbrachydactyly makes them different from other children. And having a child with this condition can make you different from other parents. You and your child may feel like you’re on your own to manage how symbrachydactyly changes your lives.

If that’s your situation, ask your child’s care team about support groups for children with congenital hand differences. Those connections may help you and your child feel less isolated.