Proposed model of the role of gp96/grp94 in the chaperone and assembly of the GPIb-IX complex. (A) gp96/grp94 binds to GPIX and promotes the normal maturation of the GPIb-IX complex, resulting in normal-sized platelets and homeostasis. (B) In the absence of gp96/grp94, GPIX and consequently GPIbβ and GPIbα are misfolded, retained in the ER, or degraded, resulting in a BSS-like disorder.