Component of the GPI transamidase complex. Essential for transfer of GPI to proteins, particularly for formation of carbonyl intermediates. Glycolipid biosynthesis; glycosylphosphatidylinositol-anchor biosynthesis. Forms a complex with PIGK/GPI8, PIGS, PIGU and GPAA1/GAA1. Has a critical role in maintaining the complex by stabilizing the expression of GPAA1 and GPI8 and linking them to PIGS. The disulfide bond between PIGK/GPI8 and PIGT is important for normal enzyme activity. The disease is caused by variants affecting the gene represented in this entry. Disease susceptibility is associated with variants affecting the gene represented in this entry. May be due to intron retention. Belongs to the PIGT family. Truncated N-terminus. Truncated N-terminus.