Frequency and Type of Genetic Abnormalities Found in Antenatal Corpus Callosum Malformation

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.