MPIG6B Gene-Related Myelofibrosis: A Rare Inherited Disease That Is Frequently Described in Arab Population.

The megakaryocyte and platelet inhibitory receptor gene G6P (MPIG6B) is located on chromosome 6p21.33. It encodes G6b-B; an inhibitory receptor expressed on the surface of platelets. It regulates platelets production, aggregation, and activation. We describe a case of a 31-year-old man who presented with a long history of thrombocytopenia, anemia, and hepatosplenomegaly. The patient received multiple blood transfusions and his clinical course was stable. A bone marrow biopsy showed morphologic features similar to primary myelofibrosis. Whole exome sequencing study was performed and revealed homozygous pathogenic mutation in exon 2 of MPIG6B gene (c.324C > A, p.Cys108Ter) that is the second reported case in literature. In this report, we describe the main clinical and pathologic features of this disease and review the literature of previously documented cases.