<p>Emberger syndrome (ES), an autosomal dominant disorder characterized by congenital deafness, primary lymphedema, and predisposition to myeloid malignancies, is caused by mutations in the <i>GATA2</i> gene. Although primary lymphedema is an important hallmark of ES, the pathophysiology remains unclear due to the lack of a suitable experimental model. In this study, we isolated induced pluripotent stem cells (iPSCs) from two patients with ES (i.e., ES-iPSCs) and analyzed their in vitro lymphatic differentiation potential via the mesodermal progenitor stage. KDR⁺ CD34⁺ early mesodermal progenitors generated from either ES-iPSCs or wild-type iPSCs during a 6-days serum- and feeder-free culture supplemented with bone morphogenetic protein 4 and vascular endothelial growth factor (VEGF) had almost equivalent developmental potential. However, upon co-culture with OP9 stromal cells, KDR⁺ CD34⁺ cells derived from ES-iPSCs developed into CD31⁺ lymphatic vessel endothelial hyaluronan receptor-1⁺ VEGF receptor 3⁺ lymphatic endothelial cells less efficiently than KDR⁺ CD34⁺ cells derived from wild-type iPSCs. Thus, patient-derived iPSCs recapitulate impairments at an early stage of lymphangiogenesis, making them a useful experimental tool for dissecting the pathophysiology of primary lymphedema in ES and developing potential therapeutic approaches.</p>