Nokea
You are consulting on a 10-year-old male with severe persistent neutropenia, a history of recurrent infections, and warts. The rest of the peripheral blood count is normal. His mother also has neutropenia. Bone marrow examination shows a hypercellular marrow and retained myeloid cells with vacuolated cytoplasm. There are no abnormalities in the red cells or platelet precursors. Cytogenetics are 46XY. You start granulocyte colony stimulating factor therapy and the neutrophil count increases. A mutation in which of the following genes is most likely to have caused this familial inherited bone marrow failure syndrome?
Correct Answer: A
Rationale: The correct answer is A: CXCR4. In this case, the patient presents with severe neutropenia, recurrent infections, and warts, suggestive of WHIM syndrome, where CXCR4 mutations are often involved. CXCR4 plays a crucial role in immune cell trafficking and retention in the bone marrow. The hypercellular marrow and vacuolated myeloid cells are consistent with WHIM syndrome. The absence of abnormalities in red cells or platelet precursors rules out other syndromes. Mutations in ELANE are commonly associated with congenital neutropenia, not familial inherited bone marrow failure syndromes. GATA2 mutations are linked to familial myelodysplastic syndromes, not typically presenting with neutropenia and warts. Mitochondrial DNA mutations are more related to mitochondrial disorders, which usually manifest with multi-system involvement, not specific to bone marrow failure syndromes.