The Silent Killer in Milk: Why Is the Galactose Test Crucial?
Galactosemia is a rare inherited disorder that can be fatal for newborns, but timely diagnosis literally saves lives. Here's what every parent needs to know.
Galactosemia is a rare inherited disorder that can be fatal for newborns, but timely diagnosis literally saves lives. Here's what every parent needs to know.
Galactosemia is a rare but extremely dangerous congenital metabolic disorder. The affected child's body cannot break down galactose, a simple sugar that is a key component of lactose, or milk sugar. According to information published on Ordinacija.hr on August 7, 2026, the only way to avoid serious and permanent organ damage is to perform testing immediately after birth, and timely diagnosis can be crucial for saving lives.
This disease is inherited in an autosomal recessive pattern and is caused by a deficiency of a key enzyme, in most cases galactose-1-phosphate uridyltransferase (GALT). Its role is to convert galactose into glucose. When the enzyme does not function, galactose and its toxic metabolites accumulate in the blood and tissues, causing severe damage to vital organs such as the liver and brain. Although the newborn initially appears healthy, the risk arises with the first intake of milk.
Without timely diagnosis, the consequences can be catastrophic. In the first weeks of life, if a child with galactosemia drinks milk, liver failure, cirrhosis, sepsis, and even death can occur. Early signs of the disease include vomiting, jaundice, lethargy, refusal to feed, and poor weight gain. Even when a strict galactose-free diet is started early, which is life-saving, patients still have a risk of long-term problems. These problems include developmental delay, speech and motor difficulties, and in girls, premature ovarian failure.
Due to the severity of the disease, testing for galactosemia is a crucial part of mandatory newborn screening in many countries. Testing is performed in the first days of life, with a blood sample taken from the baby's heel. The purpose is to detect the disease before symptoms appear, so that therapy can begin immediately and permanent consequences can be prevented. In addition to newborns, testing is also recommended for individuals with suspicious clinical signs and for family members with a history of galactosemia. Parents of a child with the disease also have access to carrier testing to assess the risk for future pregnancies.
If screening raises suspicion, the diagnosis is confirmed by specific laboratory tests. It is essential to measure GALT enzyme activity in red blood cells; if activity is very low, this confirms the disease. Levels of metabolites such as galactose-1-phosphate are also measured. For final confirmation, DNA analysis is often performed to identify mutations in the GALT gene.
Parents should be aware that a blood transfusion can give a false negative test result. Since GALT activity from donor blood can be measurable for up to four months after transplantation, other diagnostic methods are used in these cases. This information is crucial so that this dangerous disease is not overlooked.
