Like the serum Cryptococcal Antigen test (CrAg) for cryptococcal meningitis, antigen tests for talaromycosis have the potential be used for targeted screening of high-risk patients, such as people with AHD and CD4 ≤ 200 cells/mL, to facilitate early treatment before the onset of symptoms [16]. The gene discussed is CD4; the disease is mitochondrial DNA depletion syndrome 4a.