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Niemann-Pick disease is a rare genetic disorder characterized by the accumulation of macrophages, which are blood cells responsible for the defense of the organism, full of lipids in some organs such as the brain, spleen or liver, for example.
This disease is mainly related to the deficiency in the sphingomyelinase enzyme, which is responsible for the metabolization of fats inside the cells, which causes the fat to accumulate inside the cells, resulting in the symptoms of the disease. According to the organ affected, the severity of the enzyme deficiency and the age at which signs and symptoms appear, Niemann-Pick disease can be classified into some types, the main ones being:
- Type A, also called acute neuropathic Niemann-Pick disease, which is the most severe type and usually appears in the first months of life, reducing survival to around 4 to 5 years of age;
- Type B, also called visceral Niemann-Pick disease, which is a less severe type A that allows survival to adulthood.
- Type C, also called chronic neuropathic Niemann-Pick disease, which is the most common type that normally appears in childhood, but can develop at any age, and is an enzyme defect, involving abnormal cholesterol deposition.
There is still no cure for Niemann-Pick disease, however, it is important to have regular visits to the pediatrician to assess whether there are any symptoms that can be treated in order to improve the child's quality of life.
Main symptoms
The symptoms of Niemann-Pick disease vary according to the type of disease and the organs affected, so the most common signs in each type include:
1. Type A
The symptoms of Niemann-Pick disease type A usually appear between 3 and 6 months, being initially characterized by swelling of the belly. In addition, there may be difficulty in growing and gaining weight, breathing problems that cause recurrent infections and normal mental development up to 12 months, but which then deteriorate.
2. Type B
Type B symptoms are very similar to those of type A Niemann-Pick disease, but are generally less severe and may appear in later childhood or during adolescence, for example. There is usually little or no mental degeneration.
3. Type C
The main symptoms of type C Niemann-Pick disease are:
- Difficulty in coordinating movements;
- Swelling of the belly;
- Difficulty moving your eyes vertically;
- Decreased muscle strength;
- Liver or lung problems;
- Difficulty speaking or swallowing, which may get worse over time;
- Convulsions;
- Gradual loss of mental capacity.
When symptoms appear that may indicate this disease, or when there are other cases in the family, it is important to consult the neurologist or general practitioner for tests to help complete the diagnosis, such as a bone marrow test or skin biopsy, to confirm the presence of the disease.
What causes Niemann-Pick disease
Niemann-Pick disease, type A and type B, appears when the cells of one or more organs do not have an enzyme known as sphingomyelinase, which is responsible for metabolizing the fats that are inside the cells. Thus, if the enzyme is not present, fat is not eliminated and accumulates within the cell, which ends up destroying the cell and impairing the organ's functioning.
Type C of this disease happens when the body is not able to metabolize cholesterol and other types of fat, which causes them to accumulate in the liver, spleen and brain and leading to the appearance of symptoms.
In all cases, the disease is caused by a genetic change that can pass from parents to children and, therefore, is more frequent within the same family. Although parents may not have the disease, if there are cases in both families, there is a 25% chance that the baby will be born with Niemann-Pick syndrome.
How the treatment is done
Since there is still no cure for Niemann-Pick disease, there is also no specific form of treatment and, therefore, it is important to have regular monitoring by a doctor to identify early symptoms that can be treated, in order to improve the life quality.
Thus, if difficulty to swallow, for example, it may be necessary to avoid very hard and solid foods, as well as using gelatine to make the liquids thicker. If there are frequent seizures, your doctor may prescribe an anticonvulsant medication, such as Valproate or Clonazepam.
The only form of the disease that seems to have a drug that can delay its development is type C, since studies show that the substance miglustat, sold as Zavesca, blocks the formation of fatty plaques in the brain.