Two unrelated males with an intermediate hyper-IgE syndrome (HIES) phenotype were identified with mosaic variants in STAT3 [56], the gene causing AD-HIES due to dominant-negative variants in STAT3. Both patients had normal numbers of Th17 cells, frequently low in AD-HIES, but presented with chronic mucocutaneous candidiasis, staphylococcus infections, and elevated IgE. Here, STAT3 is linked to Alzheimer disease.