What Is Niemann-Pick Disease?
Niemann-Pick disease is an inherited disease that affects lipid metabolism, or the way fats, lipids, and cholesterol are stored in or removed from your body. People with Niemann-Pick disease have an abnormal lipid metabolism that causes a buildup of harmful amounts of lipids in various organs. The disease primarily affects the:
- bone marrow
This leads to enlargement of the spleen and neurologic problems.
The disease is broken down into types A, B, C, and E. Originally there was a type D, but research has found that it’s a variant of type C.
Types A and B are referred to as type 1. Type C is referred to as type 2. Type E is a less common version of Niemann-Pick that develops in adulthood.
Affected organs, symptoms, and treatments vary based on the particular type of Niemann-Pick disease. However, every type is severe and can shorten a person’s life expectancy.
The signs and symptoms of the type A form of Niemann-Pick disease are present within the first few months of life and include:
- swelling of the abdomen from enlargement of the liver and spleen, which usually occurs around 3-6 months of age
- swollen lymph nodes
- a cherry-red spot inside the eye
- difficulty feeding
- difficulty performing basic motor skills
- poor muscle tone
- brain damage along with other neurological problems, such as a loss of reflexes
- lung disease
- frequent respiratory infections
The symptoms of the type B form of Niemann-Pick disease usually begin to appear in late childhood or adolescence. Type B doesn’t include motor difficulty commonly found in type A. The signs and symptoms of type B may include:
- swelling of the abdomen from enlargement of the liver and spleen, which often begins in early childhood
- respiratory infections
- low blood platelets
- poor coordination
- mental retardation
- psychiatric disorders
- peripheral nerve problems
- lung problems
- high lipids in the blood
- delayed growth, or failure to develop at a normal rate, which causes short stature and eye abnormalities
Symptoms of the type C form of Niemann-Pick disease usually begin to appear in children around 5 years old. However, type C can appear anytime in a person’s life, from birth to adulthood. The signs and symptoms of type C include:
- difficulty moving limbs
- an enlarged spleen or liver
- jaundice, or yellowing of the skin after birth
- difficulty learning
- a decline in intellect
- difficulty speaking and swallowing
- a loss of muscular functioning
- difficulty moving your eyes, especially in an up-and-down direction
- difficulty walking
- a loss of vision or hearing
- brain damage
The symptoms of the type E form of Niemann-Pick disease are present in adults. This type is quite rare and research on the condition is limited, but the signs and symptoms include swelling of the spleen or brain and neurological problems, such as swelling within the nervous system.
Types A and B
Types A and B occur when acid sphingomyelinase (ASM) isn’t properly produced in the white blood cells. ASM is an enzyme that helps remove fats in all the cells of your body.
Sphingomyelin, the fat that ASM removes, can build up in your cells when ASM isn’t properly breaking it down. When sphingomyelin builds up, cells begin to die and organs stop functioning correctly.
Type C is primarily concerned with the body’s inability to efficiently remove excess cholesterol and other lipids. Without the proper breakdown, cholesterol builds up in the spleen and liver and excessive amounts of other fats accumulate in the brain.
The formerly-called “type D” occurs when the body cannot properly move cholesterol between cells of the brain. This is now believed to be a variant of type C.
Type E is a rare type of Niemann-Pick disease that occurs in adults. Little is known about it.
Types A and B
Your doctor will test you or your child’s blood or bone marrow to measure the amount of ASM in your white blood cells to diagnose types A and B of Niemann-Pick disease. This type of testing can help them determine whether you or your child have Niemann-Pick disease. DNA testing can also determine if you’re a carrier of the disease.
Type C is usually diagnosed with a skin biopsy stained with a special stain. Once a sample is taken, laboratory scientists will analyze how your skin cells grow, as well as how they move and store cholesterol. Your doctor may also use DNA testing to look for the genes that cause type C.
There’s no known treatment for type A at this time. Supportive care is helpful for all types of Niemann-Pick disease.
Several treatment options, including bone marrow transplants, enzyme replacement therapy, and gene therapy have been used. Research is ongoing to determine the effectiveness of these treatments.
Physical therapy helps with mobility. A medication called miglustat is currently used to treat type C. Miglustat is an enzyme inhibitor. It works by preventing your body from producing fatty substances so that less of it will build up in your body. In this case, the fatty substance is cholesterol.
Some children with the type A form of Niemann-Pick live to the age of 4. However, a majority of children with this type die in infancy.
Those with Niemann-Pick type B may survive into late childhood or early adulthood, but they often have health problems such as respiratory failure or complications related to an enlarged liver or spleen.
Niemann-Pick type C is always fatal. However, life expectancy depends on when symptoms begin. If symptoms appear in infancy, your child isn’t likely to live past the age of 5. If symptoms appear after 5 years of age, your child is likely to live until about 20 years of age. Each person may have a slightly different outlook depending on their symptoms and the severity of the disease.
Whichever type of Niemann-Pick disease you or your child may have, the sooner it’s recognized and diagnosed, the better. Research on the disease continues, and scientists are working toward more effective management and treatment of the disease.