| MYH9-related disease (MYH9-RD) is an inherited giant platelet disorder with a complex phenotype and characteristics of congenital thrombocytopenia and possible subsequent manifestations of sensorineural hearing loss, presenile cataracts, elevation of liver enzymes, and/or progressive nephropathy often leading to end-stage renal disease. Epstein syndrome, Fechtner syndrome, May-Hegglin anomaly and Sebastian syndrome, previously described as distinct disorders, represent some of the different clinical presentations of MYH9-RD. MYH9-RD is due to mutations in the MYH9 gene (22q13.1), encoding the heavy chain of the isoform A of the non-muscle myosin of class II (myosin-9). MYH9-RD is inherited in an autosomal dominant manner with sporadic de novo mutations also being observed. |
