PIEZO1 mutation: a rare aetiology for fetal ascites.

We present a case of isolated fetal ascites diagnosed at 20 weeks' gestation. No aetiology was identified on extensive prenatal workup, including prenatal microarray. The patient terminated the pregnancy at 23 weeks' gestation. Exome sequencing was performed on the products of conception, which ended up giving insight into a possible cause for the ascites. Two heterozygous missense variants of uncertain significance were identified in the PIEZO1 gene. The paternal variant has been linked to dehydrated hereditary stomatocytosis. The father of the baby suffers from haemolytic anaemia, splenomegaly and has had jaundice throughout his life. His brother and father have similar conditions. We suspect that at least one of the gene variants identified in our exome sequencing may be responsible for the illness that runs in this family, including the fetus with isolated ascites.