Identification of acquired PIGA mutations and additional variants by next‐generation sequencing in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematopoietic stem cell disorder characterized by a somatic mutation in the PIGA gene, leading to a deficiency of proteins linked to the cell membrane via glycophosphatidylinositol (GPI) anchors. While flow cytometry is the method of choice for identifying cells deficient in GPI-linked proteins and is, therefore, necessary for the diagnosis of PNH, to date there has not been an attempt to standardize the methodology used to identify these cells. In this document, we present a consensus effort that describes flow cytometric procedures for detecting PNH cells. We discuss clinical indications and offer recommendations on data interpretation and reporting but mostly focus on analytical procedures important for analysis. We distinguish between routine analysis (defined as identifying an abnormal population of 1% or more) and high-sensitivity analysis (in which as few as 0.01% PNH cells are detected). Antibody panels and gating strategies necessary for both procedures are presented in detail. We discuss methods for assessing PNH populations in both white blood cells and red blood cells and the relative advantages of measuring each. We present steps needed to validate the more elaborate high-sensitivity techniques, including the need for careful titration of reagents and determination of background rates in normal populations, and discuss technical pitfalls that might affect interpretation. This document should both enable laboratories interested in beginning PNH testing to establish a valid procedure and allow experienced laboratories to improve their techniques. (c) 2010 Clinical Cytometry Society.

PNH Education and Study Group (PESG) have been established in December 2013 as a non-profit, independent, medical organization www.pesg.org. Paroxysmal Nocturnal Hemoglobinuria (PNH) is a multi-systemic disease that should be treated with a multidisciplinary approach. Patients may apply to the clinics other than the hematology due to variability and diversity of clinical findings which lower the rate of diagnosis due to low awareness about PNH. PNH might be overlooked and diagnosis might be delayed. Regarding these, PESG was established with the collaboration of Immunology, Cardiology, Thorax Diseases (Pulmonology), Neurology, Gastroenterology, General Surgery and Urology specialists in addition to hematologists dealing with PNH. The PESG study group aims to increase the awareness about PNH, including training activities about PNH, strengthening the relations between clinics and planning of clinical studies as a goal. It is the first professional organization focusing on PNH, in Turkey.In this guideline, we want to facilitate the diagnosis attributes of physicians from all specializations that deal with PNH and its systemic complications. One can perceive this as a tailor made guideline of international guidelines but not a compilation.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hemolytic anemia characterized by the increased sensitivity of red cells to complement, leading to intravascular hemolysis and hemoglobinuria. Other clinical features are cytopenias caused by bone marrow failure and an increased risk of thrombosis. If unrecognized and not treated appropriately, PNH is often associated with a substantial morbidity and mortality. PNH is caused by the expansion of a hematopoietic progenitor cell that caries a somatic mutation in the X-linked phosphatidylinositol glycan complementation group A (PIGA) gene. The PIGA gene encodes a protein essential in the biosynthesis of glycosylphosphatidylinositol (GPI)-anchor molecules. A proportion of blood cells from patients with PNH is therefore deficient in all GPI-linked surface proteins. Considerable progress in the field of PNH research in the last 7 years has resulted from the cloning of the PIGA gene. The purpose of the current article is to describe the structure and function of the PIGA gene, to summarize the lessons learned from the analysis of PIGA gene mutations, to review the impact of mouse models on our current understanding of the human disease, and to discuss the possible pathogenesis of PNH. In addition, we will outline novel approaches to PNH diagnosis, research, and therapy that became available thanks to the cloning of the PIGA gene. Copyright 2001 by W.B. Saunders Company