Autosomal-dominant giant platelet syndromes (Fechtner, Sebastian platelet syndrome, Epstein, and May-Hegglin anomaly) display a broad spectrum of phenotypes, resulting from the different mutations in the nonmuscle myosin heavy chain 9 gene (MYH9). This evidence concerns the gene MYH9 and macrothrombocytopenia and granulocyte inclusions with or without nephritis or sensorineural hearing loss.