Neutrophil counts and function, assessed by oxidative burst with dihydrorhodamine (DHR) analysis, were normal in response to phorbol-myristate-acetate (PMA) but low in response to E. coli stimulation, in contrast to previous reports of neutropenia in other FNIP1 variants (Saettini et al. 2021), and no renal or liver cysts were found on sonography. Here, FNIP1 is linked to neutropenia.