Niemann-Pick Disease

Niemann-Pick disease (NPD) is a group of rare metabolic disorders in which harmful quantities of a fatty substance (lipids) accumulate in the spleen, liver, lungs, bone marrow, and brain. Symptoms may include lack of muscle coordination, brain degeneration, learning...

Osteopetrosis

Osteopetrosis refers to a group of rare, inherited skeletal disorders characterized by increased bone density and abnormal bone growth. Symptoms and severity can vary greatly, ranging from neonatal onset with life-threatening complications (such as bone marrow...

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;...