COUP-TFII(NR2F2) is mapped to the 15q26 deletion hotspot associated with the common and highly morbid congenital diaphragmatic hernia (CDH). Conditional homozygous deletions ofCOUP-TFIIin mice result in diaphragmatic defects analogous to the human Bochdalek-type hernia phenotype. Despite evidence from animal models however, mutations in the coding sequence ofCOUP-TFIIhave not been reported in patients, prompting the speculation that additional coding or non-coding sequences in the 15q26 locus are necessary for diaphragmatic hernias to develop. In this report, we describe a case of a patient with a heterozygous de novoCOUP-TFIIframeshift mutation, presenting with CDH and an atrial septal defect. The p.Pro33AlafsTer77 mutation specifically disrupts protein isoform 1 which contains the DNA binding domain. In addition, we review otherCOUP-TFIIsequence variations and deletions that have been described in cases of CDH. We conclude thatCOUP-TFIImutations can cause diaphragmatic hernias, and should be included in the differential diagnosis of CDH patients, particularly those with comorbid congenital heart defects. © 2016 Wiley Periodicals, Inc.