This research project aims to understand the biology and genetics of the disease myelodysplastic syndrome (MDS) in young patients. MDS is normally a disease of older persons (70+), and this study aims to determine the genetics and biology of MDS in patients diagnosed between the ages of 18 and 40 years old. MDS in young people is a distinct population with a lot of different genetic problems causing illness, most being related to the cell's repair of DNA and parts of the chromosomes chromosomes: The part of the cell that contains our DNA or genetic code. . Autoimmune and inflammatory conditions are common in MDS patients and are associated with failures in the bone marrow bone marrow: The soft, spongy tissue inside most bones. Blood cells are formed in the bone marrow. - a part of the body responsible for making blood cells. However, how common, and how seriously these mutated genes affect patients is unknown. This study will look at the entire genetic profile of 122 patients with MDS. The first step will be to look at variants in genes that are known to predispose persons with those mutations to cancers. Then we will look at genes involved in problems of the immune system in young patients with MDS. This data will be compared to a group of patients who develop MDS when aged 70 or older to see a correlation between the mutations and how those mutations manifest for patients. Afterwards, variants will be assessed to look at the type of mutation mutation: Any change or alteration in a gene. A mutation may cause disease or may be a normal variation. Paroxysmal nocturnal hemoglobinuria (PNH) occurs because of a mutation in the PIG-A gene of a single stem cell in the bone marrow. present using a variety of techniques. The purpose of this study is to help us better understand the biology of this illness and the genetic changes that cause this illness in young persons. Currently, we use stem cell transplant to treat and/or cure MDS. Knowing more about these variants will help us better choose who can donate stem cells stem cells: Cells in the body that develop into other cells. There are two main sources of stem cells. Embryonic stem cells come from human embryos and are used in medical research. Adult stem cells in the body repair and maintain the organ or tissue in which they are found. Blood-forming (hemapoietic) stem… and how to best prepare the patient for that transplant. These data can also help us and the patients to find the safest and best way to make sure that the transplant is successful by tailoring our specific treatment after transplant, which includes medications that suppress the immune system. We currently have little knowledge of how these immune phenomena and MDS in young people are connected. This study will help us to understand if MDS in young persons is a distinct entity and whether it is correlated with inborn genetic mutations or acquired mutations in genes that affect the immune system.