Mondo Description White matter hypoplasia-corpus callosum agenesis-intellectual disability syndrome is a very rare neurological condition. The few patients described in the medical literature were characterized by brain anomalies; an unusual face with broad nasal root, wide spaced eyes (hypertelorism) and a very small chin (micrognathia); failure to thrive; severe intellectual disability ;and lack of muscle tone (hypotonia). Exams of the brain showed a poor development (hypoplasia) of the pale part of the brain known as white matter, and an absent or abnormal corpus callosum (nerve fibers joining the two hemispheres of the brain). Only a few cases have being described. The cause is unknown but may be related to a disorder of axonal development. The described cases seem to be inherited in an autosomal recessive or X-linked way. Corpus callosum agenesis is one of the more frequent congenital malformations. It can be either asymptomatic or associated with intellectual disability, epilepsy, or psychiatric syndromes. It can be part of several genetic syndromes, such as Aicardi syndrome, Andermann syndrome and Apert syndrome, trisomies 13, 18 ; or result from metabolic causes; drugs (cocaine); or viral infection (influenza). Many patients with corpus callosum anomalies have other brain anomalies, including white matter hypoplasia. There is no information on specific treatment for this condition.