Eosinophilic colitis in a boy with a novel XIAP mutation: a case report.

BACKGROUND: X-linked inhibitor of apoptosis (XIAP) deficiency is a rare primary immunodeficiency disease characterized by haemophagocytic lymphohistiocytosis, recurrent splenomegaly and inflammatory bowel disease (IBD). The only curative treatment is haematopoietic stem cell transplant (HSCT). CASE PRESENTATION: Here, we report the case of a 22-month-old male with a long history of abdominal distension and anaemia. Clinical and laboratory findings were consistent with eosinophilic colitis. To identify the underlying disease, we performed exome sequencing, which showed an unreported frameshift mutation in the XIAP gene. CONCLUSION: We present eosinophilic colitis as the initial manifestation of XIAP deficiency for the first time in this article, which expands the mutation spectrum and phenotype of this disease.