Using WES in an extended family with multiple individuals affected with early-onset protein-losing enteropathy and major thrombotic events, we were able to isolate a single pathogenic variant in the complement regulator CD55, segregating with the disease.15 This finding was supported by another group describing several families with various mutations in CD55. 16 Over the years, the patients were treated only by dietary restrictions, and were often hospitalized due to abdominal complications; two family members, including a 4-year-old girl, died due to disease complications. Here, CD55 is linked to Protein-losing enteropathy.