Galactosemia is an inherited genetic disorder of metabolism where the body is unable to metabolize a sugar called galactose. Galactose forms half of the sugar lactose, which is found in milk. The other half of lactose is made of glucose.
There are three forms of this disease. These include type I or classic galactosemia, which is the most common and severe form of the disease, type II which is also referred to as galactokinase deficiency and type III which is also called galactose epimerase deficiency. The incidence of type I galactosemia is around 1 in 60,000 newborns, while type II affects fewer than 1 in 100,000 newborns and type III affects fewer still.
When an infant with galactosemia type I consumes milk, substances that are made form galactose accumulate in their body and cause damage to vital organs and bodily systems. Affected babies may develop symptoms within the first few days of life if they consume any lactose. These symptoms include the following:
- Yellowing of the skin and whites of the eyes (jaundice)
- Refusal to eat
- Poor weight gain
Galactosemia type II causes fewer problems than type I, with infants developing cataracts, but few long-term problems. The symptoms of galactosemia type III vary in severity and can include growth and developmental delay, liver disease, cataracts, kidney problems and intellectual disability.
Galactosemia is a disease that cannot be cured. The disease can only be managed in order to help prevent complications of the condition. The only way to manage galactosemia is to eliminate lactose and galactose from the diet completely. However, even when galactosemia is detected and treated early, some individuals still go on to experience long-term complications.
Some of these complications include:
- Brain damage
- Speech difficulties
- Learning disabilities
- Kidney damage
- Liver damage
- Spleen damage
- Reduced bone density
- Premature ovarian failure in females
Babies with galactosemia cannot be fed any breast milk or infant formulas containing lactose. Other products that may contain or produce galactose include casein, dry milk solids, curds and whey. It is also found in some non-milk products such as legumes, organ meats and as an additive in some food products. Instead, infants can be fed using soy-based formulas, meat-based formulas or another lactose-free formula.
Any associated health conditions that do develop should be managed by the appropriate healthcare discipline. For example, speech defects may be handled by a speech therapist and cataracts may be removed by a surgeon.
Early detection of galactosemia after a child is born is key to the control of symptoms. Without early detection and treatment, around three quarters of babies with this condition die in the first fortnight of their lives. If treated early however, a significant proportion of infants can go on to lead an almost normal life, although problems that still commonly occur include behavioral disorders, speech defects and learning disabilities. In infants with galactosemia type II, the cataracts that develop as a complication of the disease can be completely prevented if the galactose-free diet is followed.