The goal of this study is to elucidate the possible role of primary ciliary dyskinesia (PCD) in complex congenital heart disease associated with heterotaxy. This study arises from our recent finding of an unexpectedly high incidence (40 percent) of complex congenital heart disease together with heterotaxy in a mutant mouse model of PCD. These findings suggest heterotaxy can arise from mutations causing PCD. Consistent with this, a recent clinical research study showed some patients with PCD have undiagnosed heterotaxy. However, there has not been any clinical study to ascertain if patients diagnosed with heterotaxy may suffer from PCD, the focus of this IRB protocol. These studies are of immediate clinical importance, as heterotaxy patients undergoing surgical correction for complex structural heart defects can become ventilator dependent for unknown causes. A diagnosis of PCD in patients with heterotaxy would significantly alter clinical management strategies that have the potential to significantly improve outcome for heterotaxy patients undergoing high-risk cardiac surgery for complex congenital heart defects.

For this study, we will recruit pediatric subjects undergoing surgery for complex congenital heart defects associated with heterotaxy at Children's National Medical Center. We will also recruit adult patients with heterotaxy heart disease or situs inversus from the Children's National Medical Center and at NIH. Subjects will be evaluated for PCD using standard operating procedures (SOPs). This will include obtaining airway epithelial tissue samples to assess ciliary motion by videomicroscopy and for assessing defects in ciliary ultrastructure by electron microscopy. In addition, nasal nitric oxide measurements will be obtained, as reduced NO levels are often associated with PCD. All of these procedures will utilize SOPs obtained from approved IRB protocols that are part of a multi-center study at the University of North Carolina (Dr. Michael Knowles) and at the NIH (Dr. Ken Olivier, NIAID). In addition, blood, buccal swab, and saliva samples will be obtained for DNA analysis of candidate genes known to cause heterotaxy and/or PCD. Through these studies, we hope to establish whether mutations causing PCD may contribute to heterotaxy and situs anomalies. Such findings may suggest changes in the standard of care for heterotaxy patients to include the evaluation for PCD, particularly prior to surgery. In addition, the DNA analysis may provide novel insights into the genetic causes for complex congenital heart defects associated with heterotaxy and PCD, allowing the future development of appropriate diagnostic tests for more accurate identification of patients at risk for PCD. Together, the outcome of this study can have significant impact on improving the clinical care for patients with congenital heart disease associated with situs anomalies.