Galactosemia is a rare genetic metabolic disorder, characterized by the deficiency of an enzyme necessary for galactose metabolism and characterized by elevated levels of galactose in the blood.
In untreated infants with severe cases of deficient GALT activity, the following findings are typically present: Sepsis (E. coli), hypotonia, lethargy, cataracts, liver dysfunction, bleeding from coagulopathy, jaundice, poor growth within the first few weeks of life etc .
In some cases, ascites is spotted during early infancy. In rare occasions, it is diagnosed within the first few days of life. For infants or children with cataracts, galactosemia must be excluded. This is important and seeing an ophthalmologist is advised because some cataracts are not visible except through the use of a slitlamp. This is especially the case with congenital cataracts.
Although its prevalence is unknown, vitreous hemorrhage is a common complication of galactosemia. There is an enigmatic linkage of E. coli sepsis and galactosemia. Galactosemia is often high on the differential diagnosis of term infants with sepsis brought about by infection with this pathogen. Speech, language and learning problems are very common and so language acquisition might be delayed.
In adults with this condition, the most common findings include primary ovarian insufficiency in women or hypergonadotropic hypogonadism. Most black women who have variants of the disease can still get pregnant however. Neurologic abnormalities like tremor, ataxia, dystonia equally occur in most of the patients. Short stature is another minor abnormality. There have been reports of severe galactosemia in patients who went off diet therapy since childhood. This has raised concerns regarding
In many cases, workup begins with newborn screening. With a positive indication for the newborn screening quantitative erythrocyte galactose-1-phosphate uridyltransferase (GALT) analysis follows. The test has to be carried out in laboratories that perform biochemical genetic consultation and testing.
To help distinguish variant forms like the Duarte defect a GALT isoelectric-focusing electrophoresis test is conducted. GALT genotyping provides a specific molecular diagnosis in some cases. In Caucasians, the most common GALT allele is the Q188R mutation. In blacks, it is the S135L mutation .
Urine reducing substance tests will also help in establishing this defect. The results of the tests are often abnormal, in children with this problem taking in lactose diets. Rather than a dipstick test, this test is a tube test and it has to be differentiated from the normal urine dipstick test for glucose. Imaging scans like an MRI can also be used to confirm brain abnormalities.
The only treatment for galactosemia is eliminating lactose and galactose from the diet.
When left untreated, classic cases of galactosemia can be life threatening. Fortunately, medical advancements around developed countries of these world means that infants are treated before the condition gets out of hand.
If the infant with galactosemia is severely ill before treatment (with liver dysfunction, coagulopathy, sepsis) he or she may develop permanent liver, eye or brain damage. Cataracts are generally totally reversible. Patients with severe galactosemia who do not receive treatment rarely survive past the newborn period .
Again, even when the right dietary therapy is there, majority of patients show at least 1-2 complications over the long term.
Classic galactosemia cases are caused by a severe deficiency in GALT . This deficiency is a genetic condition of the autosomal recessive kind. The gene for GALT can be found on chromosome 9p13.
In the United States, the incidence of this disorder is 1 case per 40,000-60,000 individuals. Internationally, there is a wide variation in terms of incidence. For instance, this ailment is prevalent in 1 case out of 70,000 people in the UK but in Ireland, only 1 out of 20,000 people. The disorder is not commonly reported amongst Asians .
Life expectancy has not been properly documented in individuals with this defect. However, there is a high mortality rate amongst new born infants who often develop sepsis caused by Escherichia coli. With the institution of a galactose-restricted diet, most patients reach adulthood .
Galactosemia can be seen in all races but the variants are dependent on the type of gene defect. The variants are mostly seen amongst the black population. Amongst affected individuals, 10% of enzyme activity is reported in the liver but there is no activity in the erythrocytes. In places where newborn screening is not possible, the individual’s ability to tolerate the ingestion of some milk hinders diagnosis.
The Duarte variant is a recognized benign variety of the galactosemia problem. Amongst neonates with this defect, the newborn screening test results may or may not be positive and some of the neonates can easily tolerate normal diets. Such individuals may show increased galactose metabolite levels during infancy but less so in childhood .
It is still unknown whether dietary galactose restriction is necessary or beneficial for patients with the Duarte variant of galactosemia. A conservative approach which involves galactose restriction in the first year of life is taken by most metabolic disease experts. However, the restriction is largely down to the theoretical concerns of galactose toxicity in children with this Duarte variant.
Galactosemia affects both males and females equally. The disease is often diagnosed at infancy the most but variant forms of galactosemia can be diagnosed much later in adult life.
Hypergalactosemia is associated mostly with 3 major enzyme deficiencies. They are as follows:
There are no guidelines for prevention of Galactosemia.
Galactosemia in its hereditary form is a common carbohydrate metabolism condition. The disorder may be life threatening during the new born period.
First described in the variant patient in 1935 by mason and turner, GALT deficiency is the most common cause of hypergalactosemia. GALT means galactose-1-phosphate uridyltransferase .
The toxicity associated with infantile diseases can be dealt with appropriately by removing lactose However, complications occur long term .
For children who have the Galactosemia defect, a good deal of collaboration is required between the parents and the health personnel. Such children must only be given meals as prescribed by the experts.
However, you need to keep in mind that there is basically no classic diet for this defect. With different parents, doctors and clinics, different rules are followed. We have mentioned two guides followed by many nutritionist, clinics and doctors. You can get them from any closest health office to you.
It is still advised that you check with your clinic before settling for a specific diet regime. The importance of following your own doctor’s advice is important because various clinics have different recommendations.
This may add to the frustration of dealing with the condition but with proper collaboration between parents and the clinic, it becomes easier to make the best decision for the condition.