The gray platelet syndrome (GPS) is a rare inherited disorder characterized by mild to moderate bleeding tendency, moderate thrombocytopenia, and a marked decrease or absence of platelet alpha-granules and of the proteins contained in alpha-granules. The platelets are enlarged, but not giant, and have a gray appearance on light microscopy of Wright-stained peripheral blood smears due to decreased granules. Many patients with gray platelet syndrome develop a stable myelofibrosis (summary by Nurden and Nurden, 2007). Cases suggesting autosomal dominant and autosomal recessive inheritance have been described, indicating that GPS is probably a genetically heterogeneous disorder with more than one molecular cause.

Von Willebrand disease (VWD) is characterized by mucocutaneous bleeding and excessive bleeding with trauma and procedures. Individuals with more severe forms of VWD are also at-risk for musculoskeletal bleeding. Mucocutaneous bleeding can include easy bruising, prolonged bleeding from minor wounds, epistaxis, oral cavity bleeding, heavy menstrual bleeding, gastrointestinal bleeding, and bleeding with hemostatic challenges such as dental work, childbirth, and surgery. Bleeding severity can vary widely in VWD, even between affected individuals within the same family. For some with VWD the bleeding phenotype may only become apparent upon hemostatic challenge, while others may have frequent spontaneous bleeding.

Ehlers-Danlos syndrome classic-like-3 (EDSCLL3) is an autosomal dominant connective tissue disorder characterized by joint hypermobility and frequent joint dislocations, atrophic scarring, prolonged bleeding time, and age-related aortic dilatation and rupture (Hadar et al., 2024). For a discussion of genetic heterogeneity of classic-like Ehlers-Danlos syndrome, see 606408. For a discussion of the classificiation of Ehlers-Danlos syndrome, see EDSCL1 (130000).