Proposed mechanism for the cellular consequences of mutations in Shwachman-Bodian-Diamond syndrome. Left panel: Normal cell with unperturbed ribosome biogenesis and proper joining of the ribosomal subunits. Right panel: Mutations in SBDS lead to a failure to evict eIF6 resulting in a defect in subunit joining and a subsequent decrease in levels of translationally active mature 80S ribosomes. Professional illustration by Debra T. Dartez.