ASAH1 and cystic fibrosis: In respiratory epithelia, it has been shown that the increased abundance of ceramides in people with cystic fibrosis (CF) relative to those without contributes to susceptibility to endobronchial P. aeruginosa infection—a clinical presentation underpinned by inadequate acid ceramidase-coding ASAH1 gene expression and subsequent ceramide accumulation, and deficient upregulation of bactericidal sphingosine production in the presence of P. aeruginosa [263].