STAT1 and Alzheimer disease: Conversely, AD STAT1 deficiencies generally cause less severe infections in childhood, as they exert a milder effect on the IFNα/β signaling pathway, with BCGitis, multifocal osteomyelitis and Mycobacterium avium complex (MAC) infections representing the most common clinical manifestations, as demonstrated by a recent comprehensive review, which analyzed 24 cases of AD STAT1 deficiencies (16).