IDENTIFICATION OF 3 NOVEL MUTATIONS IN THE PIG-A GENE IN PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA (PNH) PATIENTS

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemolytic d isorder caused by the absence of glycosyl phosphatidylinositol (GPI)-a nchored surface proteins resulting from a defect in one step of GPI-an chor biosynthesis. Recent analysis has shown that mutations at the PIG -A (phosphatidylinositoglycan-class A) gene are responsible for GPI-an chor deficiency in all PNH patients. In the current study, we describe three new mutations of the PIG-A gene in Italian patients with PNH. T he analysis has been performed by RNA/single-strand conformation polym orphism using genomic DNA purified from nucleated peripheral blood cel ls. An abnormal pattern of migration of polymerase chain reaction ampl ified fragments containing exons 2 and 5 was observed. Sequencing anal ysis led to the identification of three mutations: a transversion C-to -A creating a stop codon (Y98X), an A insertion at position 460 (460in sA), and a C deletion (1114delC). All the mutations cause a premature termination of the translation of the PIG-A protein.