The inheritance of a CNV was determined in a subset of cases to aid in the clinical interpretation and where both parental specimens were available. Of the 1,412 CNVs with known inheritance, 566 (~40%) were found to be de novo. The majority of the de novo events (513 CNVs, ~91%) were classified as pathogenic, whereas 51 CNVs (~9%) were classified as uncertain. Two de novo CNVs, interpreted to be benign, were incidentally identified in the course of parental studies to determine the inheritance of other CNVs classified as VOUS. The de novo benign CNVs included a duplication of the beta-defensin cluster on chromosome 8p and a duplication of the CHRNA7 (MIM 118511) gene on chromosome 15q; both of these CNVs have been observed as common polymorphisms in control populations.
