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A disorder of neuronal migration characterized by partial or complete agenesis of the corpus callosum.

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Corpus callosum agenesis (CCA) is the most common cerebral malformation. It has been estimated that 0.05 to 0.7% of the general population and 2.3% of children with developmental disabilities are affected.

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Agenesis of the corpus callosum has been associated with several chromosomal rearrangements. These include autosomal dominant, autosomal recessive, and X-linked inherited syndromes.

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Unknown. An insult to the commissural plate during embryogenesis interferes with migration of the cells that form the corpus callosum. This insult can be a result of chromosomal abnormalities, be part of a syndrome, a migration, or a metabolic disorder. CCA may be an isolated anomaly or part of a syndrome with other, more extensive malformations or metabolic or genetic disorders. The corpus callosum is formed between the gestational weeks 7 and 20. Consequently, partial or complete CCA may occur if this process is disrupted. Because major parts of the cortex and cerebellum develop at the same time, associated anomalies must always be excluded. As a rule, formation of the corpus callosum starts in the front and continues to the back (holoprosencephaly is the main exception to this rule), which explains why partial callosal agenesis usually involves the posterior portion of the corpus callosum.

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Based on the clinical findings in children undergoing extensive examination for epilepsy, cognitive impairment, or, less often, behavioral problems. Computed tomography or magnetic resonance imaging confirms the absence of the corpus callosum. Frequently, there is also upward displacement and enlargement of the third ventricle (because the corpus callosum normally forms the roof of the third ventricle), widely spaced dorsal horns, and possible evidence of other migration disorders.

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Clinically and prognostically, CCA can be divided into two types. Type I is not associated with other disorders. Patients may have mild-to-moderate mental retardation and no or only mild neurologic manifestations, which may include seizure disorders and impaired visual, motor, and coordination skills. A peculiar facies with prominent forehead, macrocephaly or microcephaly, deep-set eyes, and preauricular skin tags is common. However, some patients have no clinical signs, which makes parental counseling difficult in the absence of radiologic and genetic markers allowing determination of future asymptomatic from symptomatic disease. Type II is associated with other migration, genetic, and chromosomal abnormalities, usually resulting in severe neurologic manifestations, which may include severe mental retardation, microcephaly, hemiparesis, spasticity, seizure disorder, and failure to thrive. This condition often is accompanied by recurrent bronchopneumonia and, in the severest cases, early death in infancy.

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Check for associated abnormalities, particularly metabolic disorders. Assess for complications such as seizures, paralysis, and bronchopneumonia. Preoperative investigations should include a chest radiograph, pulmonary function tests (if possible), and arterial blood gas analysis. Assess for difficult airway management in case of microcephaly. Mental retardation may affect patient cooperation. Sedative and/or anxiolytic premedication and/or the presence of the primary caregiver during induction of ...

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