The purpose of this study is to assess the neurological development at three years of age of children born after prenatal diagnosis of "isolated" agenesis of the corpus callosum.

Agenesis of the corpus callosum is the most frequent brain malformation. This anomaly may be diagnosed by ultrasound screening. In half of these prenatal cases, the anomaly seems to be isolated. In this setting, there are no prospective data concerning the development of these children, preventing any clear information to be delivered to parents. Prenatal diagnostic centers therefore face extremely variable rates of termination of pregnancies (TOP), which can reach up to 80%.

This is a multicentric prospective interventional study whose primary objective is to assess the neurological development at three years of age of children born after prenatal diagnosis of "isolated" agenesis of the corpus callosum.

Evaluation at three years will include Intellectual Quotient (IQ) quantification using the WPPSI-III, 3rd edition of Wechsler Preschool and Primary Scale of Intelligence and evaluation of intra-hemispheric coordination using the Vineland adaptative behaviour scale.

Secondary objectives will include:

• Circumstances leading to the prenatal diagnosis of agenesis of the corpus callosum
• Causes leading to termination of pregnancies
• Determination of criteria allowing to confirm that agenesis of the corpus callosum is isolated (family history, imagery, genetics)

These results could allow to determine the optimal prenatal management of such cases.

Inclusion Criteria:

• Pregnant women from 28 weeks of gestation
• Complete agenesis of the corpus callosum
• Partial agenesis of the corpus callosum
• Abnormal corpus callosum (size, anatomy) As diagnosed by an expert ultrasound fetal brain examination.

Exclusion Criteria:

• age < 18 years old
• women who do not understand french
• women not covered by the French social security system
• refusal to participate