Novel HAX1 Gene Mutation in a Vietnamese Boy with Severe Congenital Neutropenia

Abstract

Severe congenital neutropenia (SCN) is a rare disease that involves a heterogeneous group of hereditary diseases. Mutations in the HAX1 gene can cause an autosomal recessive form of SCN‐characterized low blood neutrophil count from birth, increased susceptibility to recurrent and life‐threatening infections, and preleukemia predisposition. A 7‐year‐old boy was admitted due to life‐threatening infections, mental retardation, and severe neutropenia. He had early‐onset bacterial infections, and his serial complete blood count showed persistent severe neutropenia. One older sister and one older brother of the patient died at the age of 6 months and 5 months, respectively, because of severe infection. Bone marrow analysis revealed a maturation arrest at the promyelocyte/myelocyte stage with few mature neutrophils. In direct DNA sequencing analysis, we found a novel homozygous frameshift mutation (c.423_424insG, p.Gly143fs) in the HAX1 gene, confirming the diagnosis of SCN. The patient was successfully treated with granulocyte colony‐stimulating factor (G‐CSF) and antibiotics. A child with early‐onset recurrent infections and neutropenia should be considered to be affected with SCN. Genetic analysis is useful to confirm diagnosis. Timely diagnosis and suitable treatment with G‐CSF and antibiotics are important to prevent further complication.