Immunoblotting of platelet lysates revealed severely reduced levels of GPIbα and glycosylated β1 integrin. Platelet lysates of controls, healthy relatives, and patients from both pedigrees were immunoblotted with anti-GPIbα, anti-β1 integrin, anti-β3 integrin, anti-TPO receptor, anti-VWF, and anti-β-actin as an internal control. Band intensities in blots were quantified by densitometric analysis using the ‘Image J’ software. Bar graphs represent each protein expression relative to β-actin. Impaired GPIbα and β1 integrin levels were observed in the proband from both pedigrees. VWF level was also reduced in pedigree A patients. VWF, von Willebrand factor.