Fabry’s disease: Diagnosis, Causes, Signs, Heredity and Treatment
Fabry’s disease is a rare hereditary gene defect caused by a partial or complete deficiency of a particular enzyme. The enzyme alpha-galactosidase (also: alpha-GAL enzyme), which lacks Fabry’s disease, is responsible for the decomposition of certain fatty substances in the body.
Splitting of fatty substances
If this process is disturbed, the substances cannot be digested and decomposed by the body. They are deposited instead in the cells of the entire body.
Such accumulations in blood vessels and tissues can lead to considerable malfunctions in important organ systems, for example:
- in the heart
- in the brain
- in the kidneys
In the advanced stage, Fabry’s disease can even be life-threatening to those affected.
Fabry’s disease: Diagnostics not easy
Diagnosing Fabry’s disease, however, is not always easy. Because the symptoms are manifold, often occur in the childhood or adolescent age, change or intensify quickly. Because of their rarity, the disease often remains undetected, misunderstood or even misdiagnosed. Statistically, the diagnosis of Fabry’s disease is only made after about 25 years. Until then, the patients have consulted an average of nine specialists, and their suffering is extremely high.
Often the family history provides the first suspicion. To confirm this, a simple blood test is needed in men, which shows the activity of the alpha-GAL enzyme. In the case of diseased women, quite normal enzyme values can be found despite the clear symptoms of the disease. For this reason, a more complex genetic analysis (duration: 1 to 2 months) is carried out for the clear diagnosis.
Fabry’s disease: symptoms and signs
These are typical symptoms of Fabry’s disease:
- Typical of the disease is intense, burning pain in hands and feet, which can radiate into the whole body. They usually appear in the age of children and adolescents. The pain can persist continuously (chronic) or occur in a so-called Fabry crises and then continue for minutes or days.
- Most of Fabry’s patients are sweating little or not at all, which can trigger fever blows because the body can no longer regulate its temperature.
- Very often, and usually in the youth age, reddish violet skin rashes occur in the region between the navel and knees, where the disease is often recognized. They can be a few millimetres to pinhead size.
- Many Fabry’s patients have complaints in the gastrointestinal tract, especially after eating; sometimes diarrhoea and nausea are added.
- Rarely in the adult age and as a result of a long-standing illness, there are disturbances in the heart (eg cardiac arrhythmias, heart muscle weakness, coronary artery occlusion) and the renal function diminishes (up to the dialysis requirement).
- Damage to the blood vessels in the brain is manifested by dizziness and headache; in the worst case, an early stroke occurs.
- In some Fabry disease patients, the radiating turbulence of the cornea occurs but they do not affect the eyesight and can also serve as the initial diagnosis.
Important: Not all Fabry patients have all symptoms (simultaneously). Also, the actual absence of a symptom, unfortunately, does not mean that it can not yet adjust itself. Women often have a milder course of Fabry’s disease.
Heredity and Treatment
Fabry’s patients fatigue under physical exertion quickly and are often plagued by pain. This can lead to problems in children and adolescents in school and with classmates – especially if the disease is not yet recognized and not treated. Because of the pain, many sufferers suffer from depression and hopelessness, they feel isolated and alienated from others. It can, therefore, be helpful for them to join a self-help group in which they can exchange ideas with others.
Fabry’s disease: therapy and treatment
Since the summer of 2001, it has been possible to administer the missing enzyme in the form of a regular infusion. By administering the drug, deposits in blood vessels and tissues can be prevented, existing deposits can be removed by the enzyme. With this therapy, Fabry’s patients have for the first time the chance to reach a normal age of life.
Important: The sooner the disease is detected, the better the progress can be avoided.
Fabry’s disease: frequency and heredity
Each person always inherits an X chromosome from the mother and an X or Y chromosome from the father. If the father passes an X chromosome, the child becomes female (XX); if the child inherits a Y chromosome, it becomes male (XY).
In Fabry’s disease, the defective gene is located on the X chromosome. Therefore, both men and women can carry a modified gene, because each human has at least one X-chromosome. Since Fabry’s disease is an X-linked condition, there is no inheritance of the disease from the father to the son.
However, affected fathers pass on the defective gene to all daughters. Women who have two X-chromosomes and carry the genetic defect on a chromosome can be symptomless carriers or have different degrees of disease. In any case, they carry the 50 percent risk of passing the defective gene to their offspring. Sons, who inherit the disease gene from the mother, fall ill in any case.