Fanconi-Bickel syndrome is a disorder in which glycogen storage is impaired. The disease is very rare and is synonymously referred to as glycogenosis type XI or Bickel-Fanconi glycogenosis. The disease is due to a defect on the gene ‘GLUT-2’.
What is Fanconi-Bickel syndrome?
In Fanconi-Bickel syndrome, glycogen storage in the kidneys and liver is impaired. In addition, affected patients suffer from marked renal tubulopathy and disturbances in the metabolism of galactose and glucose. Exact statements on the frequency of Fanconi-Bickel syndrome are currently not yet possible. However, no more than 200 cases of the disease are currently known. As a rule, the first symptoms of the disease appear in infants in the first months after birth. The disease usually manifests itself in symptoms such as rickets and polyuria. In this case, the proximal tubule is also affected by the disorders. Fanconi-Bickel syndrome received its name in reference to physicians Fanconi and Bickel, who first described the disease in 1949.
Causes
Fanconi-Bickel syndrome is caused by a genetic defect, making it a hereditary disease. According to study results to date, it is an autosomal recessive disease. The exact prevalence has not yet been researched, but Fanconi-Bickel syndrome is a very rare disease. The development of the disease is caused by gene mutations on the so-called GLUT-2 gene. This involves genetic mutations of both heterozygous and homozygous types.
Symptoms, complaints, and signs
In Fanconi-Bickel syndrome, the substance glycogen is accumulated in the liver of the affected patient. In addition, so-called hepatomegaly, a pathological enlargement of the liver and kidney, is evident, and the kidneys’ ability to function is severely impaired. In addition, galactose and glucose balance are disturbed. Some typical symptoms of the disease are already evident in newborns and infants. For example, rickets develops, which is associated with the disturbance of kidney function. In the further course of Fanconi-Bickel syndrome, patients suffer from symptoms such as short stature as well as a so-called renal osteopathy. In this context, hepatosplenomegaly as well as osteoporosis also occur. In young children, the disease is often initially manifested by a forward bulging abdomen resulting from hepatosplenomegaly. The pubertal phase presents later in affected individuals than in healthy adolescents. In addition, patients usually exhibit osteopenia and suffer increased bone fractures as children. With increasing age, the manifestation of osteoporosis intensifies. In some of the affected individuals, body fat is abnormally distributed.
Diagnosis
In diagnosing Fanconi-Bickel syndrome, the treating physician considers both the obvious symptoms of the disease and the results of various laboratory tests performed on the patient. When infants suffer from typical symptoms a few months after birth, appropriate medical examinations are usually ordered quickly. However, in view of the low frequency of the disease, suspicion rarely falls immediately on Fanconi-Bickel syndrome. The necessary anamnesis of the patient mainly involves the guardians of the sick child. Through them, the physician receives information regarding the symptoms of the disease. In addition, with the help of the patient’s parents, the specialist is able to take a family history, which is important for the diagnosis of the hereditary disease. After the patient interview, various examination procedures are the first priority, by means of which the physician tries to approach the present disease. For example, he uses X-ray examinations, which usually reveal evidence of rickets. Blood tests and urine samples of the patient with corresponding laboratory evaluations also play an essential role. Individuals with Fanconi-Bickel syndrome show proteinuria, phosphaturia, glucosuria, and hypophosphatemia. In addition, hyperuricemia is seen in association with aminoaciduria. Biopsies with subsequent histological analysis of the tissue samples are also possible.Doctors usually recognize a hepatic steatosis as well as a storage of glycogen in the liver and kidney, more precisely in the area of the proximal tubule cells as well as the hepatocytes. Ultimately, Fanconi-Bickel syndrome can be reliably detected by genetic testing. The gene mutations on the responsible genes are identified. In addition, prenatal diagnosis of the disease is feasible in pre-burdened families. In the differential diagnosis, the physician primarily excludes the so-called glycogen storage disease type I A, also known as Von Gierke disease.
Complications
In most cases, Fanconi-Bickel syndrome results in an enlarged liver and kidney dysfunction. Similarly, most affected individuals suffer from short stature. Especially in children, short stature can lead to difficulties as they are teased because of it. This often leads to depression and other psychological limitations. The risk of bone fractures is greatly increased by Fanconi-Bickel syndrome, so that the patient can more easily sustain injuries. In some cases, patients also suffer from an unusual distribution of body fat. This can also result in lowered self-esteem and a reduced quality of life. There is no specific treatment for Fanconi-Bickel syndrome. Therefore, it is only possible to treat the symptoms and reduce them to a minimum. The kidneys are strengthened by the addition of electrolytes. The patient must maintain a diet without galactose and take enough fructose. In general, a healthy lifestyle also has a positive effect on Fanconi-Bickel syndrome. In some cases, life expectancy is reduced if the kidney dysfunction is severe. Pain can be treated with pain therapies, but long-term use of pain medications should be discouraged.
When should you see a doctor?
Since Fanconi-Bickel syndrome does not result in self-healing or improvement of symptoms, the disease must be examined by a doctor in any case and must also continue to be treated. This is a good way to avoid further complications. The doctor should be consulted if the patient suffers from a significantly enlarged liver. Among other things, this is also noticeable through pain in this area of the body. Furthermore, the kidney function can also be disturbed, which can only be examined by a blood test. Furthermore, a visit to a doctor is necessary if the affected person suffers from short stature. Increased bone fractures or complaints when the bones grow together can also indicate Fanconi-Bickel syndrome and should be examined by a physician. Usually, the disease can be diagnosed by a pediatrician or a general practitioner. Treatment of the symptoms is then usually done with the help of medication and can limit them. Since Fanconi-Bickel syndrome can also lead to psychological symptoms, these should be managed by a psychologist or by a therapist. The syndrome itself does not usually reduce the patient’s life expectancy.
Treatment and therapy
To date, there are no effective options available for causal treatment of Fanconi-Bickel syndrome. Instead, patients’ symptoms are treated as best as possible. Impaired kidney function is treated with additional administration of electrolytes and water. Patients also receive phosphate and vitamin D. Ideally, the diseased individuals adhere to a low-galactose diet. The intake of sufficient fructose plays an important role, as this substance provides the required carbohydrates. The course and prognosis of Fanconi-Bickel syndrome have not yet been sufficiently researched. However, it has been shown that renal tubulopathy is still present in adult patients. However, it rarely results in renal impairment.
Outlook and prognosis
For the most part, Fanconi-Bickel syndrome is not life-threatening. If glycogen storage disease is recognized early and treated by a specialist, serious complications can be averted. In individual cases, however, the symptoms can develop into renal insufficiency, which is associated with further complications and is potentially life-threatening. Fanconic-Bickel syndrome also causes severe deficiency symptoms that place a protracted burden on the body.Nevertheless, the prognosis is generally positive. Patients who consult the doctor at the first symptoms and comply with the doctor’s instructions regarding diet and taking medication recover within a few months. Permanent consequences are not to be expected in Fanconi-Bickel syndrome, provided that the necessary treatment measures have been taken. Life expectancy is not reduced by the disease. Well-being is reduced during the acute phase of the disease and also during therapy, although the extent of the limitations depends on the symptom picture, the patient’s age and other factors, which must be taken into account by the physician when establishing the prognosis. Vitamin D and phospate drug therapy may occasionally lead to side effects and drug interactions that may worsen the prospect of a rapid recovery.
Prevention
Fanconi-Bickel syndrome, as a genetically triggered disease, cannot be prevented.
Follow-up care
There are usually no special aftercare options available to the affected person with Fanconi-Bickel syndrome. In this regard, the patient is primarily dependent on early diagnosis and treatment, as serious complications may occur otherwise. Since Fanconi-Bickel syndrome can only be treated purely symptomatically and not causally, genetic counseling is advisable if the patient wishes to have children in order to possibly prevent the syndrome from being passed on to the children. The syndrome is usually treated with the help of medication. Those affected must also pay attention to a high intake of fluids in order not to damage the kidneys. The internal organs should be checked regularly by a doctor in order to detect and treat damage at an early stage. A special diet is also necessary, which must be followed by the affected person. Especially in the case of children, parents should pay attention to this diet. In case of weakness of the kidneys, transplantation or dialysis may be necessary, which is why the life expectancy of the affected person may be reduced due to Fanconi-Bickel syndrome. Furthermore, care from one’s family and friends is often helpful and has a positive effect on the course of the disease.
What you can do yourself
In Fanconi-Bickel syndrome, there are very few self-help options available to the affected person. The syndrome itself cannot be prevented, so usually only symptomatic treatment by a doctor can take place. Sufferers are dependent on a low-galactose diet in their daily lives to alleviate the symptoms of the syndrome. Fruits and vegetables in particular can have a positive effect on the course of the disease, as they are rich in fructose. Furthermore, a healthy lifestyle in general also has a very positive effect on the disease. Since those affected can also suffer from weakened kidney function due to Fanconi-Bickel syndrome, electrolytes should be added to water on a regular basis. Various nutritional supplements, for example vitamin D or phosphate, can also have a positive effect on the course of the syndrome. Long-term use of these supplements should only take place after consultation with a physician. Long-term use of painkillers should also always be discussed with a medical professional. Furthermore, affected individuals depend on regular examinations of the kidneys and other internal organs to detect complaints and complications at an early stage.
