Glycosylphosphatidylinositol Biosynthesis Defect 1, also known as glycosylphosphatidylinositol deficiency, is related to hypercoagulability syndrome due to glycosylphosphatidylinositol deficiency and glucosephosphate isomerase deficiency, and has symptoms including absence seizures An important gene associated with Glycosylphosphatidylinositol Biosynthesis Defect 1 is PIGM (Phosphatidylinositol Glycan Anchor Biosynthesis Class M). Affiliated tissues include bone marrow and bone, and related phenotypes are splenomegaly and hepatomegaly