Should We Report 15q11.2 BP1-BP2 Deletions and Duplications in the Prenatal Setting?
Idit Maya, Sharon Perlman, Mordechai Shohat, Sarit Kahana, Shiri Yacobson, Tamar Tenne, Ifaat Agmon‐Fishman, Reut Matar, Lina Basel‐Salmon, Rivka Sukenik‐Halevy
Abstract
Copy number variations of the 15q11.2 region at breakpoints 1-2 (BP1-BP2) have been associated with variable phenotypes and low penetrance. Detection of such variations in the prenatal setting can result in significant parental anxiety. The clinical significance of pre- and postnatally detected 15q11.2 BP1-BP2 deletions and duplications was assessed. Of 11,004 chromosomal microarray tests performed in a single referral lab (7596 prenatal, 3408 postnatal), deletions were detected in 66 cases: 39 in prenatal tests (0.51%) and 27 in postnatal tests (0.79%). Duplications were detected in 94 cases: 62 prenatal tests (0.82%) and 32 postnatal tests (0.94%). The prevalence of deletions and duplications among clinically indicated prenatal tests (0.57% and 0.9%, respectively) did not differ significantly in comparison to unindicated tests (0.49% and 0.78%, respectively). The prevalence of deletions and duplications among postnatal tests performed for clinical indications was similar to the prevalence in healthy individuals (0.73% and 1% vs. 0.98% and 0.74%, respectively). The calculated penetrance of deletions and duplications over the background risk was 2.18% and 1.16%, respectively. We conclude that the pathogenicity of 15q11.2 BP1-BP2 deletions and duplications is low. Opting out the report of these copy number variations to both clinicians and couples should be considered.