Many genes have been linked to primary lymphedema, yet they currently explain only about 30% of the patients. Moreover, there is no cure for the disease yet. A better understanding of the underlying causes should enable the development of novel therapeutic approaches. In this study, we have detailed the clinical phenotype of patients with CELSR1 pathogenic variants, a confirmed higher penetrance in females compared to males, identified an unrecognized association with renal defects, and suggested CELSR1 as the gene behind renal problems observed in the Phelan-McDermid syndrome. We suggest CELSR1 to be included in routine genetic testing for patients with lymphedema and/or renal anomalies. (By Murat Alpaslan, M.Sc., https://jmg.bmj.com/content/early/2023/05/24/jmg-2023-109171 )