Altered 60S:40S subunit ratios are SBDS-dependent. (A) SDS patient-derived bone marrow stromal cells were infected with lentiviral vectors expressing wild-type SBDS (WT) or SBDS point mutants (K33E, R126T, R169C). An empty vector was used as a control (Ctrl). Cells were lysed in 0.25mM MgCl₂ to dissociate ribosomes into 40S and 60S subunits. Representative polysome profiles are shown for each condition. Profiles from WT SBDS (dotted lines) are overlaid for comparison with empty vector control or SBDS point mutants (solid lines). (B) 60S:40S ratio quantitation is reflective of 3 independent experiments; *P < .05.