CD55-deficiency usually manifests between ages 1-3 years. The clinical characteristics of CD55-deficiency are mostly gastrointestinal and include:
- Protein-losing enteropathy (PLE)
- Diarrhea, vomiting, distended abdomen and abdominal pain
- Peripheral and visceral edema, anasarca
- Hypoalbuminemia, hypoproteinemia, hypogammaglobulinemia
- Anemia, hypovitaminemia and micronutrient deficiencies
- Malnutrition and poor growth
- Susceptibility to large-vein thrombosis, e.g. superior vena cava syndrome, Budd-Chiari syndrome, central-line thrombosis, sinus vein thrombosis
- Intestinal biopsy may show primary intestinal lymphangiectasia
Phenotypic heterogeneity has been described among CD55-deficiency patients, meaning that not all disease features are observed in all patients; nevertheless, PLE is the key disease characteristic observed in CD55-deficiency patients. Patients may also appear asymptomatic or present only with mild hypoalbuminemia. Other gastrointestinal phenotypes, such as inflammatory bowel disease (IBD), have also been associated with CD55-deficiency.
Disease complications may include repeat intussusceptions, abdominal obstruction, and intestinal failure.