- Mirror Movement is a movement disorder where one side of the body involuntarily mirrors the movements of the other.
- Researchers in India have identified the first case of mirror movement in a patient with Turner Syndrome
- The authors of the study were unable to establish a causal relationship between the two conditions due to limited resources.
Imagine trying to type an email on your laptop but both your hands keep moving simultaneously, in an identical manner. Mirror movement is the name given to these involuntary movements and commonly occurs in the upper limbs. Although this is a common phenomenon in early childhood, it generally disappears before ten years of age as myelination of the fibers completes.
This rare movement disorder can occur along with certain neurological conditions such as Cerebral Palsy and Parkinson’s disease. Corpus callosum, the bridge that connects the two halves of the brain, is also a cause of the disorder. Its absence and a disruption of its fibers can all play a role in causing mirror movement.
However, this is the first time the movement disorder has occurred with Turner Syndrome.
Mirror Movement – One in Ever Million Children Affected
A case study published in the journal BMJ Case Reports describes the case of a 13-year-old with turner syndrome, exhibiting mirror movements. The girl had initially presented with a history of primary amenorrhea, a short height and absence of secondary sexual characteristics.
The doctors, using Karyotyping, confirmed her as a case of Turner Syndrome, a chromosomal abnormality affecting women. In Turner Syndrome, a single X-chromosome is partially or completely absent (45, XO) thus, resulting in varying effects all over the body. Effects can range from heart defects to disrupted ovarian function.
However, the presence of the movement disorder was a completely incidental finding and one the doctors were not expecting. The patient was given a task of counting on the fingers of her left hand. They discovered that her right hand also mirrored the movements. Her neurological examination was unremarkable, along with the MRI scan.
The patient was started on hormonal therapy to which she has been responding well, as written by the authors of the study.
Genetic Mutations in One-Third of Patients
Along with neurological conditions, mirror movements also occur in certain genetic mutations. This affects the development of the nervous symptom thus, disrupting the transmission of messages between the two halves of the brain.
Additionally, Kallmann syndrome can also give rise to mirror movements in individuals. It is one of the most common endocrine causes of the disorder. Kallmann Syndrome is a genetic condition characterized by a low level of certain hormones in the body. Similar to Turner syndrome, Kallmann syndrome also affects the body’s hormonal responses.
The authors of the study deny any causal relationship between Turner Syndrome and the movement disorder. They consider it to be an incidental finding. However, the availability of better imaging techniques could have helped the researchers in understanding the phenomenon better.
Mori KS, et al. BMJ Case Rep 2020;13:e238482. doi:10.1136/bcr-2020-238482
Depienne C, Cincotta M, Billot S, et al. A novel DCC mutation and genetic heterogeneity in congenital mirror movements. Neurology. 2011;76(3):260-264. doi:10.1212/WNL.0b013e318207b1e0