Clinically diverse and perinatally lethal syndromes with urorectal septum malformation sequence

Urorectal septum malformation sequence (URSMS) is characterized by a spectrum of anomalies of the urogenital system, hindgut and perineum. It is presumed to be a constellation of an embryonic defect. Herein, we analyzed the clinically diverse syndromes associated with URSMS in our perinatal evaluation unit. We reviewed fetuses with URSMS in referrals for perinatal autopsy over a period of 3 years. Chromosomal microarray and genome sequencing were performed whenever feasible. Literature was reviewed for syndromes or malformations with URSMS. We ascertained URSMS in 12 of the 215 (5%) fetuses. Nine fetuses (75%) had complete URSMS and remainder had partial/intermediate URSMS. Eleven fetuses had malformations of other systems that included: cerebral ventriculomegaly; right aortic arch with double outlet right ventricle; microcephaly with fetal akinesia deformation sequence; ventricular septal defect and radial ray anomaly; thoraco-abdominoschisis and limb defects; myelomeningocele; spina bifida and fused iliac bones; omphalocele; occipital encephalocele; lower limb amelia and cleft foot. We report on six fetuses with recurrent and five fetuses with unique malformations/patterns where URSMS is a component. Exome sequencing (one family) and genome sequencing (eight families) were performed and were nondiagnostic. Additionally, we review the literature for genetic basis of this condition. URMS is a clinically heterogeneous condition and is a component of several multiple malformation syndromes. We describe several unique and recurrent malformations associated with URSMS.