Uncertain, Not Unimportant: Callosal Dysgenesis and Variants of Uncertain Significance in ROBO1.

Congenital anomalies affect 3% to 5% of births and remain the leading cause of infant death in the United States. As whole exome and genome sequencing are increasingly used to diagnose underlying genetic disease, the patient's clinical presentation remains the most important context for interpreting sequencing results, including frequently reported variants of uncertain significance (VUS). Classification of a variant as VUS acknowledges limits on evidence to establish whether a variant can be classified as pathogenic or benign according to the American College of Medical Genetics guidelines. Importantly, the VUS designation reflects limits on the breadth of evidence linking the genetic variant to a disease. However, available evidence, although limited, may be surprisingly relevant in an individual patient's case. Accordingly, a VUS result should be approached neither as nondiagnostic genetic result nor as automatically "uncertain" in its potential to guide clinical decision-making. In this article, we discuss a case of an infant born at 29 weeks 4 days without a corpus callosum, whose whole genome sequencing yielded compound heterozygous variants both classified as VUS in ROBO1, a gene encoding for a receptor involved in a canonical signaling mechanism that guides axons across midline. Approaching the VUS result as potentially pathogenic, we found the infant ultimately had pituitary dysfunction and renal anomalies consistent with other reported ROBO1 variants and basic science literature. Accordingly, we highlight resources for variant interpretation available to clinicians to evaluate VUS results, particularly as they inform the diagnosis of individually rare but collectively common rare diseases.

Perinatal management of gastroschisis: analysis of a newly established clinical pathway.

PURPOSE: The authors developed a clinical pathway for optimal management after antenatal diagnosis of gastroschisis. This is the outcomes analysis of our first 30 consecutive patients. METHOD: Antenatal counseling was provided for all families with in-utero diagnosis of gastroschisis. Bowel dilatation, thickness, motility, amniotic fluid volume, and fetal development were followed by ultrasonography every 4 weeks. Babies were delivered by cesarean section between 36 and 38 weeks gestation if the lungs were mature or earlier for bowel complications. Gastroschisis repair was scheduled 90 minutes after birth. Primary repair was attempted in all through the abdominal wall defect without an additional incision, resulting in an umbilicus with no abdominal scar. RESULTS: Primary repair was achieved in 83%. Babies needed assisted ventilation for 3 days, reached full feeds by 19 days, and were discharged by 24 days (all medians). There were 3 (10%) deaths, all after staged repair. CONCLUSIONS: Our new protocol of both scheduled elective cesarean section and early gastroschisis repair resulted in a higher proportion of primary repair, shorter duration of mechanical ventilation, earlier full feeds, and shorter length of stay. There was no increase in mortality or morbidity. The primary-repair babies had no mortality and had excellent cosmesis.