Clinical variability in inherited glycosylphosphatidylinositol deficiency disorders.

It is estimated that 0.5% of all mammalian proteins have a glycosylphosphatidylinositol (GPI)-anchor. GPI-anchored proteins (GPI-APs) play key roles, particularly in embryogenesis, neurogenesis, immune response and signal transduction. Due to their involvement in many pathways and developmental events, defects in the genes involved in their synthesis and processing can result in a variety of genetic disorders for which affected individuals display a wide spectrum of features. We compiled the clinical characteristics of 202 individuals with mutations in the GPI biosynthesis and processing pathway through a review of the literature. This review has allowed us to compare the characteristics and the severity of the phenotypes associated with different genes as well as highlight features that are prominent for each. Certain combinations, such as seizures with aplastic/hypoplastic nails or abnormal alkaline phosphatase levels suggest an inherited GPI deficiency, and our review of all clinical findings may orient the management of inherited GPI deficiencies.