We now report the results of an 8-year study of MYH9-RD in France leading to the identification of a series of 109 patients from 37 sporadic cases and 39 unrelated families from among 295 patients with inherited macrothrombocytopenia analyzed for mutations in MYH9 in our center after phenotypic exclusion of Bernard-Soulier syndrome, Gray Platelet syndrome, Platelet-Von Willebrand Disease and Paris-Trousseau syndrome. The gene discussed is MYH9; the disease is gray platelet syndrome.