Congenital Hemolytic and Dyserythropoietic Anemias

The purpose of this study is to explore for known or yet unknown genetic mutations causative for non-immune hemolysis and/or anemia, in patients with hemoglobin disorders, membrane skeleton defects (a group of diseases including hereditary spherocytosis, hereditary elliptocytosis and pyropoikilocytosis, and hereditary stomatocytosis syndromes), RBC enzymopathies (most common of them being glucose-6-phosphate dehydrogenase (G6PD) and pyruvate kinase deficiency), and congenital dyserythropoietic anemias. The goal is to optimize genetic diagnosis for patients with non-immune congenital hemolytic anemias, and advance research on the pathogenesis and potentially improve treatment options for these rare disorders. We include analysis for genes that are known or suspected to participate in the making of healthy red blood cells. Sequencing analysis of the UDP glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) is also included because the clinical care of these patients frequently necessitate such testing to evaluate for increased risk of cholelithiasis, due to co-inheritance of Gilbert syndrome.

This is a non-interventional study, focusing on improving diagnosis and understanding the mechanisms of how abnormalities of genes may affect the making and survival of red blood cells.

The traditional tests that usually suggest the diagnosis of an erythrocyte cytoskeleton defect or a RBC enzymopathy (erythrocyte morphology in the blood smear, osmotic fragility test, and ektacytometry or enzyme activity assay respectively) do not always provide a definitive diagnosis, especially because the diagnosis with those methods requires a pure population of the patient's red blood cells, obtainable three months after last PRBC transfusion, and is therefore complicated or impossible in the patients who need frequent transfusions. Erythrocyte membrane proteins can be prepared from washed red blood cells or potentially from isolated reticulocytes from the patient. Analysis of such sample by electrophoresis on polyacrylamide gel followed by western blot for specific proteins can be a valuable tool that orients towards the diagnosis and may point to the specific gene responsible for the disease.

We propose a systematic approach to improve diagnostic evaluation of such diseases by completing a parallel analysis of ektacytometry, erythrocyte membrane proteins electrophoresis and western blot along with full exon sequencing using genomic DNA from isolated white blood cells in blood samples donated from approximately 400 patients and their parents. Our goal is to identify specific mutation(s) responsible for the patients' congenital hemolytic or dyserythropoietic anemia, and develop a genetic approach to the diagnosis of such diseases. In addition, such genetic data will offer valuable information towards understanding the pathogenesis of this group of diseases.