HAX-1 deficiency: Characteristics of five cases including an asymptomatic patient.

Background: Mutations in the HAX-1 gene cause an autosomal recessive form of severe congenital neutropenia (SCN), which particularly manifests with recurrent skin, lung and deep tissue infections from the first few months of life.

Objective: We retrospectively evaluated the clinical and laboratory findings of the patients diagnosed with SCN carrying HAX1 gene mutations.

Methods: A total of five patients with SCN, carrying a HAX1 gene mutation, were evaluated in terms of clinical and laboratory findings. Mutation analysis of the candidate genes (HAX1, ELANE and CSF3R) was performed.

Results: All of the patients lived in Turkey; four of them were of Kurdish origin and one was Turkish. Of the five patients, three were girls and two were boys, and the mean age of the patients was 8.8 years old (range 4-15 years). The mean age of diagnosis was 25.8 months (range 2 months-5 years). The infections diagnosed included recurrent gingivitis, stomatitis, and skin and soft tissue abscesses. Developmental retardation and epilepsy were present in only one patient, whereas speech retardation was present in two. All of our patients had a HAX1 mutation, and are still alive and none of them has shown malignant transformation yet.

Conclusion: Complete blood count should be performed and absolute neutrophil count should be evaluated in patients with recurrent severe infections. In the event that neutropenia is detected, they should be investigated in terms of SCN and mutation analysis should be performed.