The differential diagnosis of impaired primary hemostasis in newborns comprises von Willebrand disease, Wiskott-Aldrich syndrome, inherited platelet dysfunction disorders [e.g., GT, Bernard-Soulier syndrome and ADP receptor defect] and vascular anomalies (e.g., Kasabach–Merritt syndrome). Here, WDTC1 is linked to Wiskott-Aldrich syndrome.