Corpus callosum malformation (CCM) is the most frequently detected cerebral defect diagnosed in the prenatal setting. The most common CCM is corpus callosum agenesis (CCA) which is found in 2 to 3% of patients presenting with intellectual disability.

When CCM is diagnosed, the risk of chromosomal disorder is estimated to be 16%, be it aneuploidy such as trisomy 18, trisomy 13 or mosaic trisomy 8, or a chromosome structure anomaly, copy number variation or more complex rearrangement In France, since 2013 oligoarray-based comparative genomic hybridization (aCGH) analysis is performed in the prenatal period for most malformations after approval by a multidisciplinary prenatal diagnosis ethics committee (Centre Pluridisciplinaire de Diagnostic Prénatal, CPDPN) . However, to date only a few studies have been published which report recurrent Copy Number Variations (CNV) associated with CCM and estimate the risk for a chromosomal disorder, thus making counseling difficult in this context of prenatal diagnosis.

Inclusion Criteria:

• Prenatal diagnosis of corpus callosum malformation, isolated or not, between 01/01/2013, and 31/05/2018
• Fetal DNA available
• Mother's informed consent obtained

Exclusion Criteria:

• No amniocentesis performed
• Refusing to participate

Fetuses with prenatal diagnosis of corpus callosum malformation and antenatal molecular analysis by array CGH performed