Evidence for autosomal dominant inheritance in prenatally diagnosed CHAOS.

Congenital high airway obstruction syndrome (CHAOS) is a rare prenatal diagnosis consisting of a typical fetal triad of large hyperechogenic lungs, flattened or inverted diaphragms and ascites. Most cases are sporadic with unknown incidence. Before attempts of fetoscopic fetal salvage or ex utero intrapartum treatment (EXIT) are considered, additional malformations must be carefully excluded as CHAOS may be part of various monogenic conditions or chromosomal disorders. We report an unique family with autosomal dominant inheritance of CHAOS and variable expression in the affected father and two affected children. It is concluded that minor expression in one of the parents may be an important indicator for genetic counseling in CHAOS and management of future pregnancies.