PIGT is one of over 29 glycosylphosphatidylinositol biosynthesis defect (GPIBDs) genes. Mutations cause genetically determined disorders characterized mainly by epilepsy with fever-sensitivity, central hypotonia, psychomotor delay and congenital malformations. The disease is known as Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 3 (MCAHS3) or Glycosylphosphatidylinositol Biosynthesis Defect-7. Twenty-eight cases have been reported until today. We present seven novel Polish patients, all harbouring 1582G>A variant in a homozygous or compound heterozygous state which seems to cause a milder phenotype of the disease. This article is protected by