Ring chromosome 6 syndrome is a rare chromosomal anomaly syndrome with highly variable phenotype principally characterized by prenatal/postnatal growth failure, intellectual disability, developmental delay, craniofacial dysmorphism (incl. microcephaly, microphthalmia, epicanthus, low-set and malformed ears, broad and flat nasal bridge, full lips, micrognathia), central nervous system anomalies (e.g. hydrocephalus, cortical atrophy, ventriculomegaly), short neck, and delayed bone age. Cardiac defects, limb anomalies, hip joint malformations, and seizures have also been reported.

In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences.