Clinical Characteristics

Congenital mirror movements are characterized by contralateral involuntary movements that mirror voluntary ones. While mirror movements can be occasionally seen in otherwise healthy children, persistence of mirror movements beyond age of 10 years is considered abnormal. Mirror movements tend to occur more commonly in the upper extremities (fingers and hands, but may also be present in the forearms, toes, and feet) and persist throughout adulthood.

Isolated agenesis of the corpus callosum, partial or complete, is a finding on neuroimaging and may be associated with a range of intellectual disabilities (normal to borderline impaired). In addition, specific cognitive impairments, including language delay or visuospatial deficits have been reported in patients with monoallelic variants in DCC.

Developmental split brain syndrome is characterized by horizontal gaze palsy, childhood onset progressive scoliosis, global developmental delay, delayed walking and intellectual disability. Neuroimaging findings include agenesis of corpus callosum, absence of anterior and hippocampal commissures, hypoplasia of the pons and midbrain, and midline cleft throughout the brainstem.