Case Report of Rare Cause for Fetal Ascites and Postnatal Hemolytic Anemia [Conference Winner Abstract]

Introduction This report presents a case of isolated fetal ascites diagnosed at 29 weeks gestation caused by a pathogenic heterozygote variant in the PIEZO1 gene detected postnatally during a genetic consultation due to anemia of unknown etiology. Genetic testing was not done during pregnancy, but it would explain the prenatal condition. Case Presentation A 30-year-old woman (gravida 1, para 0) at 29 weeks gestation presented for a routine ultrasound to detect possible anatomical abnormalities. Isolated fetal ascites was diagnosed. The woman had a repeated ultrasound at 33 weeks showing almost no ascites present. Natural delivery at 41 weeks occurred with no complications. At 2 years old the female child was referred for a hematologist consultation due to low hemoglobin, high MCV, MCH, and reticulocytes. After clinical genetics consultation, a blood disorders NGS panel was ordered. It revealed heterozygous pathogenic PIEZO1 gene variant c.7483_7488dup that causes amino acid duplication p.Leu2495_Glu2496dup. The variant was inherited from the father who received a diagnosis after the child’s testing. Phenotype data and genetic test results were compatible with autosomal dominant stomatocytosis (a rare hemolytic anemia) with or without perinatal edema. Detection PIEZO1 gene variant explains the isolated fetal ascites during pregnancy. Discussion Fetal ascites can be idiopathic or caused by various reasons, but it is important to diagnose and follow up on it due to possible complications and risk of fatality. [1] In this case fetal ascites was most likely caused by a pathogenic variant of the PIEZO1 gene and the postnatal presentation of it was stomatocytosis. It is known that this gene codes for the component of red blood cells [2], which would explain anemia. [3] This case shows how complete anamnesis can explain pathological changes and help with the diagnosis ante and postnatally. [4] Conclusions Postnatal genetic and phenotype testing explains prenatal fetal ascites and confirms the exact diagnosis of stomatocytosis. However, due to spontaneous regression of fetal ascites prenatally, the diagnosis was not confirmed timely as no genetic testing was performed during pregnancy.