An X-linked recessive inherited disorder caused by loss of function mutations in the PIGA gene. It is characterized by deficient GPI-anchor synthesis. Patients may develop somatic paroxysmal nocturnal hemoglobinuria (PNH) or multiple congenital anomalies-hypotonia-seizures syndrome 2 (MCAHS2; early infantile epileptic encephalopathy 20; EIEE20). [from
NCI]