PIGM deficiency is caused by the mutation of PIGM, an mannosyltransferase which transfers first mannose to GlcN-(acyl)PI, generating ManGlcN-(acyl)PI in the fifth step of the GPI biosynthesis. This disease is caused by the decreased expression of various GPI anchored proteins, which serve critical functions as adhesion molecules, receptors, complement regulators, enzymes and co-receptors in signal transduction pathways. There are only four families reported until now, showing the same homozygous mutation in the promoter region of PIGM gene, the main symptoms of which are portal vein or cerebrovascular thrombosis and epilepsy without developmental delay, which is quite different from other IGDs. The prevalence of PIGM deficiency is unknown as it is recently recognized disease, but there have been only four unrelated families with the same mutation of the promoter region reported. The PIGM gene is located on chromosome 1q23.1, and PIGM deficiency is autosomal recessive disorder.
PIGM