A familial congenital mirror movement disorder where individuals with heterozygous variants in DCC have congenital mirror movements and/or agenesis of the corpus callosum (not with or without- some individuals do not demonstrate mirror movements and only have corpus callosum defects, even within the same family). The disease is Monarch Disease Ontology id MONDO_0100515 (mirror movements 1 and/or agenesis of the corpus callosum).