Gray platelet syndrome (GPS), or platelet alpha-granule deficiency, is a rare congenital autosomal recessive bleeding disorder caused by a reduction or absence of alpha-granules in blood platelets, and the release of proteins normally contained in these granules into the marrow, causing myelofibrosis. The name derives from the initial observation of gray appearance of platelets with a paucity of granules on blood films from a patient with a lifelong bleeding disorder. Signs and symptoms
Signs of GPS typically arise at birth or in childhood, these signs and symptoms include thrombocytopenia, bruising susceptibility, and epistaxis. Typically, the observed low platelet count in individuals is progressive, this can result in fatal hemorrhages later in life. Additionally, females who are affected may experience irregular menstrual cycles and heavy menstrual bleeding. Another common effect of GPS is myelofibrosis, where scar tissue builds up in the bone marrow causing it to be unable to produce a sufficient amount of blood cells. To compensate, other organs such as the spleen start to produce more blood cells which can lead to splenomegaly. Genetics
GPS is primarily inherited in an autosomal recessive manner. The gene that is mutated in GPS has been mapped to chromosome 3p and identified as NBEAL2. The location is 3p21.31. This is caused by a homozygous or compound heterozygous mutations in the NBEAL2 gene. NBEAL2 encodes a protein containing a BEACH domain that is predicted to be involved in vesicular trafficking. It is expressed in platelets and megakaryocytes and is required for the development of platelet alpha-granules.
Prognosis is generally good early in life when thrombocytopenia is mild. Epidemiology
Currently, only 60 cases have been recorded worldwide. While the prevalence of this syndrome is not known, it was found that it affects males and females equally. See also
Pseudo gray platelet syndrome
Giant platelet disorder

References
External links

Gray platelet syndrome at NIHs Office of Rare Diseases