Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a condition in which the body makes too many activated immune cells (macrophages and lymphocytes). People with HLH usually develop symptoms within the first months or years of life. Symptoms may include fever, enlarged liver...

22q11.2 Deletion Syndrome Overview

Bernice Morrow, PhD, discusses 22q11.2 deletion syndrome, a disorder caused by the deletion of a piece of chromosome 22.     22q11.2 deletion syndrome is a disorder caused by the deletion of a small piece of chromosome 22. It has a variety of symptoms that...

Mitochondrial Genetic Disorders

Mitochondrial genetic disorders refer to a group of conditions that affect the mitochondria (the structures in each cell of the body that are responsible for making energy). People with these conditions can present at any age with almost any affected body system;...

Myelodysplastic/Myeloproliferative Disease

Myelodysplastic/myeloproliferative diseases are a group of diseases of the blood and bone marrow in which the bone marrow makes too many white blood cells. These diseases have features of both myelodysplastic syndromes and myeloproliferative disorders. In...

Congenital Hyperinsulinism

Congenital hyperinsulinism is a condition causing abnormally high levels of insulin, a hormone that helps control blood sugar levels. People with this condition have frequent episodes of low blood sugar (hypoglycemia). In infants and young children, these episodes are...