A heterozygous ITGA9 missense variant has been implicated in several cases of recurrent congenital chylothorax and fetal hydrops.21 The inheritance pattern for ITGA9 chylothorax is unknown; though an autosomal recessive mechanism has been proposed, the majority of cases are heterozygous inherited from unaffected parents.21,55 Given the reduced penetrance seen in other LAs, this may suggest autosomal dominant inheritance. This evidence concerns the gene ITGA9 and Chylothorax.