Niemann-Pick disease is a genetic disorder that impairs the body's ability to break down certain kinds of fat called lipids. Doctors and medical researchers have identified several types of the disease based on the specific genetic defect involved and the symptoms that are caused. Niemann-Pick disease can cause a host of health problems in infants and young children, including liver and spleen failure and brain damage that can significantly impair cognition and development. The disease cannot be cured, treatment measures are primarily designed to ease a child's symptoms and slow the progression of ultimately fatal complications.
The two most common forms of Niemann-Pick disease are types A and B. Both diseases result from an inherited recessive gene that prevents cells from producing an enzyme known as acid sphingomyelinase. Without the enzyme, cells cannot effectively break down certain naturally-occurring lipids in the body. As a result, lipids build up in the liver, spleen, and brain. Type C Niemann-Pick disease originates with a different kind of genetic defect that impairs the body's ability to break down cholesterol and other fats from food, leading to many of the same problems caused by the other two types.
Type A is generally prevalent in early infancy; type B symptoms usually develop in later childhood or once the child has become an adolescent; and type C may not cause noticeable symptoms until a child is of school age. All three types can cause abdominal pain and swelling, speech impairment, and failure to thrive. An infant with type A may not be able to ingest and process food without the aid of a feeding tube. Seizures are common in children with type C, and an individual may not be able to control eye or motor movements.
Doctors diagnose types A and B when blood samples do not contain sufficient levels of acid sphingomyelinase. Type C is confirmed when blood samples contain high levels of cholesterol and skin tissue samples reveal abnormal cholesterol storage patterns. Once a diagnosis has been made, a doctor can discuss possible treatment methods with the patient's family.
Treatment for patients with Niemann-Pick disease varies depending on the type, but all are difficult to treat. Type A is generally considered not treatable, while a few patients with type B have been bone marrow transplants with some success. Patients with type C may be placed on strict, low-cholesterol diets and given medications to ease internal organ inflammation and swelling. Even with treatment, infants with type A Niemann-Pick disease rarely live past the age of three. Type B and C patients generally have a better prognosis, with some patients surviving to adulthood.
