Management of copy number variants associated with incomplete penetrance and variable expressivity-Results of a French survey.

Increasing interest regarding neurodevelopmental disorders and democratization of chromosomal microarray analysis have led to growing identification of neuro-susceptibility copy number variations (CNVs). These CNVs have incomplete penetrance and variable expressivity (PIEV), which makes phenotypic features hard to predict. The French Consortium "AchroPuce" has provided a list of 17 CNVs that should be considered as PIEV CNVs. This list led to consensual French practices of healthcare professionals in postnatal diagnosis. However, no consensus was established in prenatal diagnosis and fetal pathology. 121 French health professionals were surveyed their opinions and practices regarding reporting of PIEV CNVs to patients, in order to identify key points so as to establish French recommendations. The survey showed that professionals in favor of reporting PIEV CNVs to patients in prenatal diagnosis and fetal pathology (respectively, 76% and 84% of respondents) considered highlighted that multidisciplinary consultation is the main point-of-care management before family survey. This statement is close to recommendations published worldwide. As a consequence, multidisciplinary expertise should be the basis of French recommendations concerning the reporting of PIEV CNVs and genetic counseling in prenatal diagnosis and fetal pathology.