WHIM syndrome (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) is a rare genetic disorder caused by mutations in the CXCR4 gene. These mutations lead to abnormal immune cell behavior, resulting in a weakened immune system. Individuals with WHIM syndrome experience recurrent bacterial infections, low levels of antibodies (hypogammaglobulinemia), and myelokathexis, where mature neutrophils (a type of white blood cell) are trapped in the bone marrow, leading to neutropenia. A hallmark symptom is the development of persistent warts caused by human papillomavirus (HPV), which can sometimes lead to cancer. 

Symptoms can vary from mild to severe, with common infections affecting the respiratory system, skin, and gums. Severe cases may result in bronchiectasis, respiratory failure, or heart failure. Diagnosis involves blood tests revealing low neutrophil and immunoglobulin levels, along with genetic testing to confirm CXCR4 gene mutations. 

Treatment focuses on managing symptoms, including the use of antibiotics to combat infections, immunoglobulin replacement therapy to boost immune function, and granulocyte-colony stimulating factor (G-CSF) to increase neutrophil production. In 2024, the FDA approved Mavorixafor, a CXCR4 inhibitor, to enhance neutrophil and lymphocyte counts in patients 12 years and older. Research on CXCR4 inhibitors and bone marrow transplants is ongoing.