GP1BA and Macrothrombocytopenia: In contrast, macrothrombocytopenia, even with giant platelets, is typical of alterations in the GP1BA, GP1B, GP9, MYH9, SRC, and SLFN14 genes, and in the majority of ITs from variants in genes that encode cytoskeletal proteins or participate in glycosylation [1,2,4].