X-linked cerebral-cerebellar-coloboma syndrome is a rare genetic condition that mainly affects brain development. It is characterized by a malformation in the cerebellum, including a small or missing cerebellar vermis (hypo- or aplasia), enlarged brain ventricles (ventriculomegaly), a missing corpus callosum (agenesis of the corpus callosum), and other abnormalities in the brainstem and cerebral cortex. These changes can impact how the brain controls movement and other functions. Along with these brain differences, ocular coloboma is a key feature, meaning that there is a gap or notch in eye structures which may impair vision. At birth, people with this condition can experience hydrocephalus (an excess buildup of fluid in the brain) and low muscle tone (hypotonia) accompanied by unusual breathing patterns. As they grow, severe delays in motor and mental development (psychomotor delay) and seizures are common.

People with this condition may show several neurological and ocular symptoms. Common signs include hydrocephalus at birth, neonatal hypotonia (low muscle tone), and abnormal breathing patterns. Eye issues such as coloboma can cause impaired vision, and there are frequent reports of severe psychomotor delays and seizures.

X-linked cerebral-cerebellar-coloboma syndrome is caused by a genetic change in the CCCSX gene. This condition follows an X-linked pattern, meaning the genetic alteration is on the X chromosome. Males, having only one X chromosome, are more often affected while females may serve as carriers. The mutation leads to the structural brain differences and eye abnormalities seen in this syndrome.