Piga, encoding phosphatidylinositol N-acetylglucosaminyltransferase subunit A, is crucial for the biosynthesis of glycosylphosphatidylinositol (GPI) anchors. GPI-anchored proteins are involved in cell signaling, immunity, and adhesion, highlighting the gene's overall biological importance. Drosophila models have been used to study PIGA-CDG, providing insights into the disease mechanism [5].

Somatic mutations in Piga in bone marrow hematopoietic stem cells lead to paroxysmal nocturnal hemoglobinuria (PNH), characterized by hemolytic anemia, thrombosis, and peripheral blood cytopenias due to uncontrolled complement activation from the absence of GPI-anchored proteins CD55 and CD59 [2,3,7]. Germ-line Piga mutations can cause multiple congenital anomalies-hypotonia-seizures syndrome 2 (MCAHS2) and PIGA-related congenital disorder of glycosylation (PIGA-CDG), which are associated with hypotonia, developmental delay, intractable seizures, and a high risk of premature mortality [1,4,6].

In conclusion, Piga is essential for GPI anchor biosynthesis, with its dysfunction leading to various disorders. Studies using models like Drosophila help in understanding the role of Piga in disease conditions such as PNH, MCAHS2, and PIGA-CDG, contributing to a better understanding of the underlying disease mechanisms.