[3] Consequently, patients with this movement disorder have serious difficulty carrying out tasks that require manual dexterity or precision, such as playing a two handed musical instrument or typing on a keyboard, for their whole lives.

[3] That is, patients who have inherited a mutated dominant allele, along with their genetically affected parent, can be symptomatic or asymptomatic for CMM disorder.

[4] The genes that currently have evidence to be associated with CMM disorder include DCC (deleted in colorectal carcinoma), DNAL4 (dynein axonemal light chain 4), and RAD51 (recombination protein A).

[9] Kanga mice, lacking the P3 intracellular domain of the DCC receptor, show a hopping gait, moving their hind legs in a strictly paired fashion, as do kangaroos.

[8] In CMM disorder patients, researchers found splice site mutations on DNAL4, which caused skipping of exon 3, and thereby omission of 28 amino acids from DNAL4 protein.

[7] RAD51 heterozygous mutations, specifically premature termination codons, have been found in many CMM disorder patients through genome-wide linkage analysis and exome sequencing.

[6][19] The normal disappearance of clinically significant mirror movements after this age is associated with anatomical and functional maturation of interhemispheric connections through the corpus callosum between motor cortices.

This might provide an alternate explanation for the presence of mild mirror movements in normally developing young children that typically disappear before the age of 7.

[24] Some researchers propose that DCC mutations cause a reduction in gene expression and less robust midline guidance, which may lead to a partial failure of axonal fiber crossing and encourage development of an abnormal ipsilateral connection.

[2] Clinical Findings (Signs and Symptoms)[1][2][10][26][14]: Molecular genetic testing[1]: CMM has clear severe impacts on a patient's ability to carry out daily manual tasks.

[27][17] It is recommended that children be placed under more forgiving school environments, allowing more time for written evaluations and limiting handwritten assignments, to ease the burden of the movement disability.

[2][5] Because of its pronounced and obviously noticeable signs and symptoms, CMM patients can suffer social stigma; however, physicians need to make it clear to parents, family, and friends that the disorder bears no relation to intellectual abilities.