Morbus Meulengracht (Gilbert-Meulengracht disease, Gilbert-Meulengracht syndrome) is a congenital, harmless metabolic disorder. Due to the reduced activity of an enzyme, the red blood pigment is only insufficiently degraded. The eyes can turn yellow, sometimes headaches and tiredness occur. Patients should pay attention to a few things in order to relieve the metabolism. Read all about the causes, symptoms and treatment options of Morbus Meulengracht.
Morbus Meulengracht: description
“Morbus” is a Latin term meaning “disease”. The name “Meulengracht” comes from the Danish physician Jens Einar Meulengracht, who has contributed significantly to the study of metabolic disorder. In the case of Morbus Meulengracht, the breakdown of the red blood pigment hemoglobin is disturbed.
Hemoglobin is located in the red blood cells (erythrocytes). After about 120 days of life they are sorted out by the body and degraded to make room for fresh blood cells. The hemoglobin is released and degraded in the spleen, liver and bone marrow.
First, it is converted to the non-water-soluble bilirubin and transported to the liver. There is an enzyme called UDP-glucuronosyltransferase, which makes the bilirubin water-soluble.
The water-soluble bilirubin then enters the intestine with the bile, which gives it its yellowish color. There it is further converted to dark brown stercobilin and finally excreted with the stool. A certain amount of bilirubin (about 20 percent) takes the intestine back into the body, a small part is excreted in the urine. Therefore, the urine is yellow in color.
Hemoglobin degradation in Morbus Meulengracht
In Meulengracht’s disease, UDP-glucuronosyltransferase is less functional and accounts for only about 30 percent of normal degradation work. Therefore, the concentration of non-water-soluble bilirubin in the blood increases. In this case we speak of hyperbilirubinemia.
Since the UDP-glucuronosyltransferase is still working in part and the water-insoluble bilirubin can also be converted by indirect routes into the water-soluble form, this hyperbilirubinemia keeps in moderation.
Important: In the case of Morbus Meulengracht the liver is not damaged. Only the enzyme activity in the organ is reduced. The amount of bilirubin produced poses no danger to the body. In some other metabolic diseases such as the so-called Crigler-Najjar syndrome UDP-glucuronosyltransferase almost completely failed. In this case, the concentration of water-insoluble bilirubin increases so much that the consequences can be severe.
Who is affected by Morbus Meulengracht?
About nine percent of the population show this metabolic disorder. Men are more likely to suffer from Morbus Meulengracht, white-skinned people are more frequently affected than dark-skinned.
Morbus Meulengracht: symptoms
The main feature of the disease is a yellowing of the sclera (that part of the eyeball that otherwise appears white). The skin may also turn yellow in rare cases. Unlike many liver or biliary disorders but there is no itching. The symptoms usually appear only after puberty and are often the first and only sign of the disease of Meulengracht.
In many people affected, the yellowing of the eyes only appears when certain factors such as sports or alcohol consumption. It is not harmful, but it is a cosmetic problem. Sometimes, however, there are other symptoms such as:
- Tiredness / fatigue
- Headaches to migraine attacks
- Abdominal pain and nausea
The extent of the complaints does not correlate with the level of bilirubin.
Morbus Meulengracht: cause and risk factors
The hypofunction of UDP-glucuronosyltransferase in Morbus Meulengracht is caused by a genetic defect. It is therefore an inborn metabolic disorder. Children with an affected parent have a significantly higher risk of the disease.
Certain factors increase blood bilirubin levels and may increase the symptoms of Meulengracht’s disease. These factors include:
- alcohol consumption
- Nicotine consumption (smoking)
- very low-fat diet
- certain medications
- greater athletic effort
Myoglobin is a protein in the muscles that has properties similar to hemoglobin. It supplies the muscles with oxygen. The breakdown of myoglobin proceeds as in hemoglobin. Accordingly, in an increased degradation of muscle cells, for example during exercise, increased bilirubin.
The effect of medication can be influenced
There are also drugs that further reduce the activity of UDP-glucuronosyltransferase. So-called protease inhibitors used in HIV therapy are an example of this.
At times, agents of drugs linger longer in the body than desired due to the decreased activity of UDP-glucuronosyltransferase. This may increase their effect or cause more side effects. Affected here are, for example, the following drugs:
- cholesterol lowering agents such as simvastatin or atorvastatin
- estrogen-containing supplements like the anti-baby pill
- Painkillers such as ibuprofen, paracetamol or buprenorphine
The use of certain medications should therefore always be discussed with a doctor.
Morbus Meulengracht: examinations and diagnosis
Frequently, Morbus Meulengracht is detected in a routine blood test when the level of bilirubin in the blood is increased. Sometimes, however, the affected person first noticed the yellowing of the sclera. In this case, a doctor should be consulted. This will first inquire about the exact course of yellowing and other complaints. This is followed by a physical examination.
The total bilirubin level in the blood should be less than 1.1 milligrams per deciliter. People with Morbus Meulengracht often have values between two and five milligrams per deciliter. Higher values indicate another illness. For example, Crigler-Najjar syndrome is often associated with bilirubin levels in excess of 20 milligrams per milliliter. Newborns have different values.
In order to clearly diagnose the disease of Meulengracht, one carries out a so-called fasting or nicotinic acid test. It is checked if the bilirubin level in the blood rises after a few days of fasting or after taking nicotinic acid. In some cases, a molecular genetic examination can detect the responsible genetic defect.
Morbus Meulengracht: treatment
Since Morbus Meulengracht in many cases causes no discomfort and does not pose a serious threat to health, usually no therapy is needed. In addition, with some rules of conduct one can keep the bilirubin content in the blood low.
Morbus Meulengracht: nutrition
Longer periods of hunger lead to an increase of bilirubin in the blood. Therefore, people who suffer from Morbus Meulengracht, should not perform fasting. Even low-fat foods increase the bilirubin content in the blood. Otherwise, those affected can eat normally.
Two other factors increase the bilirubin content in Morbus Meulengracht: alcohol and nicotine. Both stimulants should therefore be avoided.
Morbus Meulengracht: Disease course and prognosis
Morbus Meulengracht runs in most cases completely harmless, only very rarely affect the symptoms of those affected. The older the patients become, the less likely they are to experience discomfort. Often they disappear altogether in old age.
It is believed that the mortality of people with low hyperbilirubinemia is not increased. Some studies even suggest that increased bilirubin protects against certain lung diseases and reduces mortality. The cosmetic problem that can arise from the yellowing of the eyes is for people with Morbus Meulengracht sometimes a burden.