Mirror movements are involuntary movements of a side of the body that mirror intentional movements on the opposite side. Mild mirror movements are physiologic in young children and gradually disappear within the first decade of life, likely due ... Mirror movements are involuntary movements of a side of the body that mirror intentional movements on the opposite side. Mild mirror movements are physiologic in young children and gradually disappear within the first decade of life, likely due to maturation of the motor network. Mirror movements that persist beyond age 10 years represent a rare disorder usually showing autosomal dominant inheritance with incomplete penetrance (summary by Depienne et al., 2012).
Depienne et al. (2011) and Depienne et al. (2012) reported a large 4-generation French family in which 8 individuals had congenital mirror movements. Affected individuals had involuntary mirror movements affecting the hands and forearms, resulting in functional disability ... Depienne et al. (2011) and Depienne et al. (2012) reported a large 4-generation French family in which 8 individuals had congenital mirror movements. Affected individuals had involuntary mirror movements affecting the hands and forearms, resulting in functional disability in fine manual activities, and in pain and cramping during sustained manual activities, including writing. The disorder showed a stable course, and none required treatment. There were no associated disorders. An unrelated German family with 2 affected individuals had a similar phenotype.
By exome sequencing of a large French family with mirror movements reported by Depienne et al. (2011), Depienne et al. (2012) identified a heterozygous truncating mutation in the RAD51 gene (179617.0003). The mutation was found in 8 affected ... By exome sequencing of a large French family with mirror movements reported by Depienne et al. (2011), Depienne et al. (2012) identified a heterozygous truncating mutation in the RAD51 gene (179617.0003). The mutation was found in 8 affected individuals and in 8 unaffected individuals, indicating incomplete penetrance. A second truncating mutation in the RAD51 gene (179617.0004) was identified in a German family with the disorder. The authors concluded that haploinsufficiency was the pathogenic mechanism. Rad1 expression was found in the developing mouse cortex, and specifically in a subpopulation of corticospinal axons at the pyramidal decussation. The mechanism linking RAD1 deficiency to the disorder was unclear: insufficient RAD51-related DNA repair during early corticogenesis might lead to excessive apoptosis and altered central nervous system development; however, RAD51 may have a direct or indirect role in axonal guidance.