Western blot analysis of GPIbβ in platelet lysate. Platelet lysate from a normal individual and the affected brother was analyzed by immunoblotting with an anti-GPIbβ polyclonal antibody. A total of 11 μg and 168 μg of protein was loaded on the gel from the normal individual and patient respectively. GPIbβ is readily detectable in the normal control but is significantly reduced in the patient.