Uniprot Description A form of non-immune hydrops fetalis, a condition characterized by fluid accumulation in at least 2 fetal compartments, including abdominal cavities, pleura, and pericardium, or in body tissue. The majority of hydrops fetalis cases are non-immune conditions that present with generalized edema of the fetus. Approximately 15% of non-immune cases result from a lymphatic abnormality. HFASD is an autosomal dominant, lymphatic-related form with variable expressivity. Some patients suffer from severe manifestations that can result in early death, whereas others have milder clinical features, such as atrial septal defect or varicose veins as adults. The hydrops and/or swelling improves spontaneously in those who survive the neonatal period.