Involuntary 'mirrored' movements reflection of gene mutation

When Andrée Marion brushes her teeth or combs her hair with one hand, her other one makes the same motion at the same time. When she fishes for change in her pocket with her left hand, the fingers on her right hand look like they are crawling.

Many members of her large Quebec family, including her 19-year-old son, make the same kind of involuntary mirror movements, and now Ms. Marion knows why. They have a rare genetic mutation that affects the development of the nervous system.

Normally, the right side of the brain directs the muscles on the left side of the body and vice versa. But in the case of family members with the mutation, the signals go to both sides, says the University of Montreal's Guy Rouleau, a senior member of the team of scientists that studied Ms. Marion's family.



The work on the genetically unusual Marions is an important step toward understanding how the human brain and body are wired in the womb and early infancy, says Dr. Rouleau, and may help shape future therapies that could involve using stem cells to replace or repair damaged brain cells and nerves.

Like most of the 11 affected members of her family, Ms. Marion has mirror movements in her fingers and hands. Three of her relatives, however, also get them in their toes and feet.

Sometimes she can override the movements – when she is typing with both hands, for example. Like the others in her family, she first saw it as quirk, nothing to ask a doctor about. Then one of her cousins, suffering from an unrelated problem, consulted a Montreal neurologist, who noticed the mirror movements and was intrigued to hear other family members also experienced them.

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