Niemann-Pick disease is a rare genetic disorder that renders the body incapable of metabolizing cholesterol and other lipids inside of cells. The result is a buildup of these fatty substances in various areas of the body, including the brain.
There are three main types of Niemann-Pick disease, each of which has its own symptoms, onset, and life expectancy. There is currently no cure for Neimann-Pick disease, so the treatment centers around managing the condition and extending life expectancy.
The outlook for people with this disease will vary depending on which type they have and at what age the symptoms first appear. However, Niemann-Pick disease is generally fatal.
Keep reading to learn more about Niemann-Pick disease, including its causes, diagnosis, and treatments and the outlook for people living with it.
Niemann-Pick disease is a rare genetic condition that prevents the body from effectively breaking down fatty substances. This inability to process fats and lipids leads to rapid accumulation that damages vital organs.
Doctors categorize Niemann-Pick disease into A, B, and C types. Niemann-Pick disease type C (NPC) has two variations — NPC1 and NPC2 — depending on which gene it involves.
Each variation manifests differently with unique symptoms, but all the types are serious and will cause complications. Although people with type A or B tend to develop symptoms early in life, type C can present at any time.
The disease is extremely rare, with only 500 reported cases of NPC worldwide and 1,200 cases of types A and B (NPA and NPB). It is a life threatening disorder, particularly for younger people. For instance, in a study involving people with NPB, the fatality rate among those under the age of 21 years was
NPC is somewhat treatable, but the disease is often fatal depending on how progressive it is and how it attacks the body. It tends to be most severe when its onset is immediate following birth or when it develops late and goes undiagnosed until adulthood.
NPA and NPB result from a deficiency in the enzyme acid sphingomyelinase (ASM), which the body needs to break down a lipid called sphingomyelin. When there is insufficient ASM to metabolize this lipid, it builds up in the cell, leading to cell death and organ dysfunction. The deficiency results from mutations in a gene called SMPD1.
The National Neimann-Pick Disease Foundation explains that people with NPA and NPB usually have less than 1% and about 10%, respectively, of the normal amount of ASM.
NPC typically transmits genetically via autosomal recessive inheritance, which occurs when an individual inherits a mutated gene — NPC1 or NPC2 — from each of their parents. The parents of children with Niemann-Pick disease do not usually have the condition.
The National Organization for Rare Disorders reports that 95% of people with NPC have a mutation in NPC1, which is located on chromosome 18. When NPC2 mutations occur, these affect chromosome 14.
The symptoms of Niemann-Pick disease vary among the different types of the disorder.
The signs and symptoms of type A usually occur within the first few months after delivery. They may include:
- intellectual disability
- psychiatric disorders
- impaired coordination, known as ataxia
- delayed growth
- peripheral nerve problems
Type B typically produces signs and symptoms that begin in childhood or adolescence. Most people with this type do not have neurologic symptoms, but they may have:
- enlarged liver and spleen
- frequent respiratory infections
- “cherry-red spot,” which doctors identify with an eye exam
- swollen lymph nodes
- difficulty feeding
- visual impairment
The common signs and symptoms of NPC include:
- speech difficulties
- severe liver disease
- abnormal eye movements
- enlarged liver and spleen
The diagnosis of Niemann-Pick disease centers around clinical observations and blood or skin cell biopsies. Doctors use biopsies to measure the levels of ASM, which helps them determine white blood cell production.
A blood sample or biopsy will measure the progression or severity of Niemann-Pick disease, revealing its type. However, doctors sometimes misdiagnose the disease or delay diagnosis because they do not recognize it at first. As it is so rare, most doctors see few — if any — cases of Niemann-Pick disease throughout their career.
The type of Niemann-Pick disease will determine the treatment options.
No treatments are currently available for Type A, which is typically fatal within the first few years of life.
Doctors treat NPB with enzyme replacement therapy, bone marrow transplants, and
Doctors employ a range of physical therapy and medicinal solutions to treat NPC. People typically take migulstat, an enzyme inhibitor that prevents the body from producing fatty substances, such as cholesterol. This treatment reduces fat buildup, thereby mitigating the effects of type C.
As each type of Niemann-Pick disease manifests differently, the outlook and life expectancy vary.
The majority of children with NPA do not survive beyond their first few years due to the severity of the symptoms.
NPB, which is also known as juvenile onset Niemann-Pick disease, usually occurs in preadolescence. Although it shares some symptoms with NPA, its symptoms are usually less severe. It is not uncommon for individuals with NPB to live into adulthood.
NPC is also incurable, but the outlook for people with this disease ultimately depends on when complications begin.
Although all those with the disease have it from birth, the symptoms may sometimes not become apparent until later in life. If the symptoms appear in infancy or childhood, life expectancy is often less than a few years. However, if they develop after the first few years of life, life expectancy extends to adulthood.
Niemann-Pick disease is a rare genetic condition that prevents the body from effectively breaking down fatty substances. These fats and lipids rapidly accumulate in bodily tissues, damaging vital organs.
There is no known cure for Niemann-Pick disease and no way to prevent it because it is entirely hereditary. However, early diagnosis and proper treatment may improve life expectancy for some people with type B or C.