Persistent patency of the ductus arteriosus, or patent ductus arteriosus (PDA), is the second most common congenital heart disease, affecting approximately 1 in 1,600 to 5,000 live births in the U.S. (Mitchell et al., 1971). In fetal life, the ductus arteriosus, a muscular artery, shunts blood from the pulmonary artery to the aorta, bypassing the lungs. Its abrupt closure at birth establishes the mature circulatory pattern and represents a dramatic example of vascular remodeling. Failure of this normal process results in persistent PDA, which left untreated can result in pulmonary hypertension and heart failure. Closure of the ductus is a complex process. Aspects of this process are regulated by oxygen tension and a decrease in levels of hormones such as prostaglandin E2. PDA occurring in preterm infants often closes spontaneously or in response to inhibitors of prostaglandin biosynthesis (Ramsay et al., 1987). Term PDA typically has not been regarded as a genetic disorder, because it most often occurs sporadically. Nonetheless, term PDA recurs among 5% of sibs of PDA cases (Polani and Campbell, 1960; Lamy et al., 1957), suggesting a genetic component to disease pathogenesis that has typically been presumed to be multifactorial. That single genes can influence this trait has been demonstrated by a mouse model of PDA resulting from disruption of the prostaglandin E2 receptor (Nguyen et al., 1997) and by rare syndromic forms of PDA such as Char syndrome (169100), an autosomal dominant disorder caused by mutations in the transcription factor TFAP2B (601601) (Mani et al., 2002). Genetic Heterogeneity of Patent Ductus Arteriosus Autosomal dominant forms of patent ductus arteriosus include PDA2 (617035), caused by mutation in the TFAP2B gene (601601) on chromosome 6p12, and PDA3 (617039), caused by mutation in the PRDM6 gene (616982) on chromosome 5q23. Hajj and Dagle (2012) reviewed the genetics of patent ductus arteriosus in both term and preterm infants, and discussed possible environmental risk factors as well as animal models of PDA. [from OMIM]

Char syndrome is characterized by the triad of typical facial features, patent ductus arteriosus, and aplasia or hypoplasia of the middle phalanges of the fifth fingers. Typical facial features are depressed nasal bridge and broad flat nasal tip, widely spaced eyes, downslanted palpebral fissures, mild ptosis, short philtrum with prominent philtral ridges with an upward pointing vermilion border resulting in a triangular mouth, and thickened (patulous) everted lips. Less common findings include other types of congenital heart defects, other hand and foot anomalies, hypodontia, hearing loss, myopia and/or strabismus, polythelia, parasomnia, craniosynostosis (involving either the metopic or sagittal suture), and short stature. [from GeneReviews]