Severe congenital neutropenia in 2 siblings of consanguineous parents. The role of HAX1 deficiency.

Severe congenital neutropenia (SCN) is a rare primary immunodeficiency disease that is characterized by persistent severe neutropenia and severe early-onset bacterial infections. We report the case of 2 siblings with SCN who were the children of consanguineous parents. The HAX1 mutation was identified in both siblings. Both patients suffered from oral ulcers, candidiasis, respiratory tract infections, and diarrhea. A bone marrow biopsy, performed to determine the cause of their persistent severe neutropenia, revealed myeloid maturation arrest; thus confirming the diagnosis of SCN. Granulocyte colony-stimulating factor and prophylactic antibiotics were started. A molecular study revealed a homozygous W44X mutation of the HAX1 gene in both cases. HAX1 deficiency should be considered in any child with severe infections and neutropenia, especially in children of consanguineous parents. Early diagnosis and appropriate treatment could prevent complications in this group of patients.