The term storage disease refers to a group of diseases characterized by deposits of various substances in organs or cells. Storage diseases include lipidoses or hemosideroses, for example.
What is storage disease?
Storage diseases can occur in different forms and manifestations. However, all diseases have in common that substances are stored in cells and organs. Depending on the site of deposition and the substance, different symptoms develop. In glycogenoses, glycogen stored in body tissues is only incompletely broken down. Glycogenoses include, for example, Hers disease or Pompe disease. In mucopolysaccharidoses (MPS), glycosaminoglycans accumulate in the lysosomes. MPS therefore belong to the group of lysosomal storage diseases (LSDs). These include Hunter syndrome or Sanfilippo syndrome. The collective term lipidoses covers hereditary metabolic diseases that are associated with an abnormal accumulation of fats in the tissues and cells. Typical lipidoses are Wolman’s disease and Niemann-Pick disease. Sphingolipidoses are inherited storage diseases in which there is an accumulation of sphingolipids in cells. Fabry disease or Gaucher disease are sphingolipidoses. Among the best known storage diseases are the hemosideroses. In hemosiderosis, iron is deposited in the organism. In the amyloidoses, intracellular and extracellular deposition of protein fibrils occurs.
Causes
Many storage diseases are hereditary. For example, glycogen storage diseases are usually based on an enzyme defect. In von Gierke disease, for example, glucose-6-phosphatase is damaged; in Tarui disease, it is phosphofructokinase. The majority of mucopolysaccharidoses are also inherited. There is a lack of enzymatic cleavage of glycosaminoglycans, resulting in accumulation in the lysosomes of the body cells. Many lipidoses are due to reduced or defective function of lysosomes. Therefore, liposes are classified as lysosomal storage diseases. Mutations in genes encoding the lysosomal enzymes result in a complete loss of activity. As a result, lipid metabolism is disrupted and lipids accumulate in the tissues. Sphingolipidoses, similar to liposes, are also due to lysosomal enzyme defects or to enzyme deficiencies. Hemosideroses may be acquired or congenital. Acquired hemosideroses occur as a result of increased iron intake. In particular, blood transfusions or transfusions of red blood cell concentrations can cause increased deposition of iron in the body. Hereditary hemochromatosis, on the other hand, is an autosomal recessive inherited disease.
Symptoms, complaints, and signs
In glycogen storage diseases, symptoms are quite variable. There is enlargement of the heart, liver, or kidneys. Affected individuals are often hypoglycemic. Blood lipid levels are elevated. Hyperuricemia may also occur. As the disease progresses, hemorrhagic diatheses often develop. In hemosideroses, toxic cell damage results from iron deposition in the organs. In the liver, hemochromatosis leads to liver cirrhosis. The risk of liver cancer also increases significantly. In the pancreas, fibrosis leads to insulin deficiency, resulting in diabetes mellitus. In the heart, iron deposition leads to cardiac arrhythmias and, in the worst case, to heart failure. In the joints, a so-called pseudogout develops. In men, there is a risk of infertility. Amyloidoses are associated with increased protein excretion in the urine (proteinuria), neuropathies, dementia, liver enlargement, hair loss and joint complaints. There is also swelling of the liver and spleen in liposes. Furthermore, psychomotor decline is observed. In children, developmental disorders, hearing loss, and spasticity occur within the first year of life.
Diagnosis and course of the disease
Initial clues to the presence of storage disease are provided by the usually quite characteristic symptoms. Depending on the suspected diagnosis, various examinations are performed. Imaging techniques such as X-ray, ultrasound, CT or MRI provide evidence of organ damage or organ enlargement.In laboratory diagnostics, various blood parameters such as glucose, creatine kinase, iron or proteins can be determined. Which parameters are determined in the laboratory depends on the suspected diagnosis and the symptoms present. Often, a biopsy of the affected organs and tissues can confirm the diagnosis. In the case of amyloidoses, for example, the phenomenon of ham spleen is found in the biopsy. The appearance of the sliced spleen is reminiscent of a sliced ham due to the incorporation of protein fibrils.
Complications
In general, the exact complications and symptoms of storage disease depend very much on its severity and also on which components cannot be stored in the cells. For this reason, a general prediction is not possible in most cases. However, those affected suffer from severe enlargement of the liver or heart as a result of the disease, so that pain can occur in these organs. Likewise, the kidneys can also be affected by enlargement. In the further course, the liver is damaged due to the disease and the affected person dies. Likewise, disturbances to the heart rhythm occur and sufferers may experience heart failure. In many cases, storage disease also leads to psychological symptoms and developmental disorders. Especially in children, the disease can lead to severe disorders. Treatment of storage disease always depends on the underlying disease. There are no particular complications. However, if the organs have already been damaged, transplantation or surgery may be necessary. Possibly, the life expectancy of the affected person will be significantly reduced.
When should you see a doctor?
Storage disease should always be evaluated and treated by a physician. Since self-healing does not occur with such a disease, a medical professional must be consulted. Only proper medical treatment can prevent further complications. In most cases, the patient with a storage disease is dependent on lifelong treatment. A doctor should be consulted if there are symptoms of the internal organs. In most cases, the patient’s blood values deviate from the normal values. This can also affect the heart, and in the worst case, complete insufficiency can occur, leading to death. In many cases, hair loss may indicate a storage disease, and children in particular may suffer from developmental disorders or even spasticity. If these symptoms occur, a doctor must be consulted in any case. A storage disease can be detected by a general practitioner. Further treatment itself then depends on the exact complaints and on their severity and is carried out by a specialist.
Treatment and therapy
Therapy depends on the underlying disease. Hereditary hemochromatoses, for example, are treated with phlebotomy therapy. Instead of phlebotomy, blood donation can also be performed on a regular basis. Alternatively, the drug deferoxamine is used. A low-iron diet can also positively influence the course of the disease. If detected early enough, patients with hemochromatosis have a normal life expectancy. Amyloidoses are treated medicinally with diuretics, ACE inhibitors, CSE inhibitors, and amiodarone. Patients may need additional dialysis. The insertion of a pacemaker may also be required. In lipidoses, no causal therapy is often possible. Depending on the form, patients die in childhood. Symptomatic therapy aims to prevent the absorption and accumulation of fats and cholesterols. Statins, for example, are used for this purpose. For many storage diseases, it is important to start therapy before the onset of the first symptoms. In this way, the course of the disease can often be positively influenced. Very few storage disorders are curable.
Prevention
Because most storage diseases are inherited, prevention is not possible. Only acquired hemosiderosis can be prevented by controlled transfusions and concerted iron supplementation.
Follow-up
In most cases, the options for direct follow-up of salivary disease are limited. In many cases, the disease itself cannot be treated causally because it is very often a genetic condition.Therefore, the affected person should ideally see a doctor at a very early stage. If a person wishes to have children, a genetic examination and counseling should first be carried out in order to prevent the recurrence of the storage disease. It is not possible for this disease to cure itself, so the affected person should contact a doctor at the first symptoms and signs of this disease. In most cases, this disease can be relatively well alleviated by taking various medications. Regular intake and the prescribed dosage should always be observed in order to properly limit the symptoms. Likewise, if there are any questions or side effects, a doctor should always be consulted first. Also, regular checkups and examinations are very important to regularly monitor the current status of the storage disease. If the storage disease is treated, the life expectancy of the patient is usually not reduced.
What you can do yourself
In everyday life, any situation of overload or physical strain should be avoided. At the first signs of overexertion, the affected person needs rest and relief. Taking regular breaks helps to prevent any discomfort. The disease represents a challenge for the organism in coping with it. In the context of self-help, therefore, every effort should be made to build up situations of relief. Stressors should be avoided and emotional stability is important. Both contribute to minimizing disturbances of the heart rhythm. At the same time, the pressure on organs or functions of the organism decreases. Relaxation techniques such as yoga or meditation help to establish inner stability. If the course of the disease is unfavorable, the life expectancy of the affected person is reduced. Therefore, the affected person should inform himself sufficiently in advance about the possible developments and take any precautions. This leads to mental states of overload being reduced under certain circumstances. The diet should be reviewed and optimized if necessary. The intake of fats and cholesterol should be avoided, as these lead to an increase in symptoms. A healthy and balanced diet will help to alleviate the adverse health effects. In addition, adequate exercise in fresh air is equally beneficial for stabilizing the body’s defense system.