Congenital mirror movement disorder is a condition in which intentional movements of one side of the body are mirrored by involuntary movements of the other side. For example, when an affected individual makes a fist with the right hand, the left hand makes a similar movement. The mirror movements in people with this disorder primarily affect the arms, and the hands and fingers are always involved. This pattern of movements is present from infancy or early childhood and usually persists throughout a person's life.

Congenital mirror movement disorder is caused by variants (also called mutations) in at least three genes: DCC, RAD51, and NTN1.

Congenital mirror movement disorder is a very rare disorder. Its prevalence is thought to be less than 1 in 1 million individuals. Researchers suggest that it may be more common as some mildly affected individuals may never be diagnosed.

Congenital mirror movement disorder is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the altered gene. Some people who have the altered gene never develop congenital mirror movement disorder; this is known as reduced penetrance.

Published Date: May 19, 2025
Published By: National Institutes of Health