Differential Diagnosis: Congenital Macrothrombocytopenia

Differential diagnosis of congenital thrombocytopenia is important in the diagnosis of autoimmune thrombocytopenia. Congenital macrothrombocytopenia is a heterogeneous group of rare disorders, characterized by abnormally giant platelets and thrombocytopenia since birth. The most common are MYH9 disorders and heterozygous Bernard-Soulier syndrome. In many of congenital macrothrombocytopenias, defects are associated with platelet cytoskeleton or adhesion molecules and their receptors. Thus, molecular diagnosis targeting subcellular localization or surface expression of defective gene product is available, and thus a definite diagnosis is possible in approximately 60% of cases.