PIGM and hypercoagulability syndrome due to glycosylphosphatidylinositol deficiency: Inherited glucosylphosphatidylinositol (GPI) deficiency or PIGM-CDG is caused by a mutation in the core promoter of PIGM, severely impairing the binding site of the transcription factor Sp1 and resulting in hindered transcription (Almeida et al., 2006).