One patient, initially suspected of having ITP, was confirmed to have MYH9-related thrombocytopenia, two cases initially diagnosed with ITP were confirmed as Bernard-Soulier syndrome, three cases of ITP were reclassified as unspecified inherited thrombocytopenia, and two patients initially suspected as having von Willebrand disease were reclassified as unspecified inherited platelet function disorder. Here, MYH9 is linked to inherited thrombocytopenia.