Any form of galactosemia corresponds to a metabolic disorder and is characterized by enzyme deficiency. The disease is based on a genetic mutation that results in disorders in the cleavage of galactose into glucose. Since no causal treatment option is available for affected individuals, the prognosis for patients in many cases is conceivably unfavorable.
What is galactosemia?
Galactose is a natural, sweet monosaccharide with the molecular formula C6H12O6. The substance represents an important metabolite within the human organism. The intestine absorbs galactose ingested with food in order to supply it to the liver and to introduce it into the carbohydrate metabolism via enzymatic processes. The processes of galactose metabolism can be disturbed by different conditions. A congenital disorder of the metabolic pathway is present in patients with galactosemia. Affected individuals cannot adequately metabolize the monosaccharide. As a consequence, their galactose blood level increases. Disturbances in galactose metabolism can cause carbohydrate metabolism to come to a complete standstill. Different enzymes play a role in the metabolic pathway. Any deficiency of these enzymes is a pathological condition. Different subtypes of galactosemia exist, characterized by different degrees of severity and referred to as GALT, GALK, and GALE galactosemia.
Causes
Underlying each form of galactosemia is a deficiency in galactose metabolic enzymes. Known as GALT-galactosemia, galactose-1-phosphate uridyltransferase deficiency is the most common galactosemia. The prevalence is reported as one case per 40,000 newborns. Less commonly, galactosemia is due to galactokinase or UDP-galactose 4-epimerase deficiency. Neither enzyme causes symptoms as long as the deficiency state remains incomplete. Only when one of the enzymes is completely absent do symptoms occur. The primary cause of each form of galactosemia is a genetic mutation. GALT galactosemia involves a mutation in the GALT gene on chromosome 9. Like the other two forms, GALT galactosemia can be inherited. The inheritance is autosomal recessive. The consequence of the GALT mutation is a disturbance in the conversion of galactose to glucose. This results in excessive accumulation of galactose-1-phosphate in organs such as the liver, brain, kidneys and erythrocytes. Toxic damage is done to each of these systems.
Symptoms, complaints, and signs
The first symptoms of galactosemia manifest in the neonatal period. In addition to weakness in drinking, vomiting occurs. Patients also frequently show jaundice. Septic conditions may occur. Liver dysfunction in affected individuals increases the longer milk feeding is continued. Coagulation disorders of Quick values below ten percent occur in association with an increase in transaminases. Affected children bleed from the puncture canals with marked prolongation. The eye lenses become cloudy bit by bit (cataract). The more the disease progresses, the more apathetic the children become. In the late stages, they lose consciousness. The liver coma occurs. Only a few children survive this critical phase. Survivors often suffer from mental impairment, hormone-deficiency-related ovarian dysfunction, or blindness later in life.
Diagnosis
In the past, the diagnosis of galactosemia was not made until the stage of hepatic coma. With medical advances in recent decades, the diagnosis can now be made by simple detection of the toxically damaged erythrocytes. In addition, the activity of the affected enzymes can be determined by the Beutler test. Test methods also exist for galactose-1-phosphate and galactose. Since the recent past, nationwide newborn screening for the disease has become common. The prognosis is rather unfavorable for patients with galactosemia. In many cases, they go into hepatic coma shortly after birth.
Complications
Galactosemia causes metabolic symptoms. In most cases, the patient suffers from weakness in drinking and severe vomiting at a very young age. Since fluid is also lost through vomiting, dehydration occurs, which is a very unhealthy condition for the patient. Furthermore, jaundice may also occur.Galactosemia also causes discomfort and complications in the eyes, leading to the development of cataracts. In the worst case, this can lead to the complete loss of the patient’s vision and thus drastically reduce the quality of life. In the further course, the so-called hepatic coma also occurs and many affected persons lose consciousness. As a rule, galactosemia cannot be treated causally, so that the affected person is dependent on a strict diet for the rest of his or her life. The baby food must also be adapted accordingly. However, vegetables are also unsuitable for the patient, resulting in severe restrictions in food intake. These restrictions often lead to developmental disorders and retardation. Sometimes parents are psychologically burdened by galactosemia and suffer from depression.
When should one go to the doctor?
If parents notice weakness in drinking as well as vomiting in their child, galactosemia may be present. A doctor should be consulted if the symptoms have not subsided after one to two days at the latest. If there are also signs of jaundice, an immediate visit to the doctor is indicated. Symptoms of cataracts and apathetic behavior are also clear warning signs that must be clarified. If galactosemia is not treated, there is a risk of hepatic coma, which requires intensive medical care in any case. The metabolic disease mainly affects children who are deficient in certain galactose metabolic enzymes. If such a deficiency has been diagnosed, the symptoms mentioned should be clarified immediately. After initial treatment, further medical examinations are usually necessary. If there are signs of mental impairment, visual disturbances or malfunction of the ovaries, the child should be taken to the doctor in charge. Accompanying therapeutic treatment is usually also useful. Especially children who suffer from permanent damage as a result of the disease require additional support from a psychologist and/or psychotherapist.
Treatment and therapy
Causative therapy is not yet available for patients with galactosemia. At most, gene therapy would be a conceivable causal approach for genetic disorders. To date, however, gene therapy is not in the clinical phase. Galactosemia patients are therefore only treated supportively. Not even a promising symptomatic treatment is available for them. One supportive therapy step is a lifelong lactose-free and low-galactose diet. All foods with a high galactose content are taboo. This includes, above all, foods such as milk and dairy products. Even commercially available lactose-free milk is not suitable for patients with galactosemia. The lactose is broken down into galactose and glucose during the manufacturing process. Thus, although lactose-free milk products are lactose-free, they still contain galactose. For newborns, the supportive diet measure is particularly difficult. They also have to give up breast milk and conventional baby food. Alternatives include products such as infant formula based on soy. Legumes such as peanuts and peas are also eliminated from the diet of all galactosemia patients. These products contain substances that are broken down by the intestine into glalactose. In vegetables, in turn, free galactose is present, so vegetable products are also unsuitable for those affected. Even in the area of body care, it is important to pay attention to the ingredients of individual products. Creams, toothpastes and soaps, for example, are often contaminated with lactose. Even if all the above steps are followed, developmental disorders can still occur. The human body itself produces galactose to a certain extent. This endogenous galactose can result in developmental delays. Reduced intelligence may be addressed with early intervention.
Outlook and prognosis
The prognosis of galactosemia is unfavorable in many patients. Complete recovery or freedom from symptoms has not been documented. Based on legal as well as medical options, the genetic disease cannot be cured at the present time. Rather, a dramatic development occurs immediately after birth in a large number of newborns. Many infants fall into a comatose state within the first minutes of their lives.The risk of suffering a hepatic coma is significantly increased in galactosemia sufferers. This means that life expectancy is reduced. In addition, there is a risk of suffering various complications as well as lifelong limitations. There is also no adequate treatment option for galactosemia, which is aimed at the complete alleviation of symptoms. The therapy is aimed at promoting well-being. Depending on the symptoms, individual countermeasures are introduced. A special diet is used to support the treatment. Avoiding dairy or vegetable products and certain cosmetics significantly improves the patient’s general well-being. If there is a reduction in mental performance, an improvement in cognitive abilities can be achieved with early intervention programs. In the case of general disorders of the child’s development, various measures of support are also offered. They contribute to an improvement in the general quality of life.
Prevention
Galactosemia can be prevented exclusively through genetic counseling during the family planning phase. Couples at increased risk of inheriting the disease may decide against having their own children and consider adoption instead.
Follow-up
In most cases, galactosemia does not provide any particular options for follow-up care. The affected individual is primarily dependent on direct and medical treatment by a physician for permanent relief of symptoms. As a rule, lifelong treatment is necessary, since galactosemia cannot be treated causally. Since the condition is also a hereditary disease, genetic counseling can be provided if the patient wishes to have children in order to prevent the disease from being passed on to the children. In galactosemia, the affected person is dependent on a special diet. Dairy products should be avoided. If dairy products are consumed, medication can also be taken so that the body can digest them. As a rule, a doctor can also be consulted in this case, who can draw up a diet plan for the patient. In many cases, contact with other galactosemia sufferers also has a positive effect on the course of the disease, as this can lead to an exchange of information. Particular complications usually do not occur with this disease and there is also no reduced life expectancy of the affected person.
What you can do yourself
Galactosemia requires medical treatment in any case. Affected parents can support therapy by keeping a close eye on the child and consulting a physician immediately if unusual symptoms are observed. Weakness in drinking can be alleviated by conscious stimulation of the lips, floor of the mouth and tip of the tongue, as an adjunct to drug treatment. Most children respond positively to these stimuli, and in many cases sucking on the finger also turns into a natural drinking reflex. Milk should be given from a drinking bottle, as this allows better control of the amount taken. It is advisable to note down the amount of liquid taken in and to talk to the pediatrician in charge in case of strong deviations from the required amount. Gentle abdominal massages are helpful against nausea and vomiting, as are certain natural remedies, for example chamomile tea or applications with valerian. Professional advice is also needed for vision problems. Parents should first and foremost make sure that the child does not fall or injure himself as a result of the reduced vision. If the symptoms do not subside despite all the measures taken, a further visit to the doctor is indicated. There may be a serious condition that needs to be clarified and treated.
