Galactosemia is a rare hereditary disease in which galactose metabolism fails. This failure leads to galactose accumulation in the blood and body tissues.
Galactose results from the conversion of lactose into glucose and galactose. Lactose is a sugar that is present in human, cow, and formula milk. Also, it’s present in fruits and vegetables like tomato, banana, and apple. In healthy people, the human body converts galactose into glucose to produce energy.
Your baby appears healthy at delivery, and the symptoms start to appear after few days of delivery due to ingestion of human milk (that contains lactose). Your baby will lose his appetite and complain of vomiting, jaundice, hepatomegaly, proteinuria, and ascites. Also, he may complain of growth failure, diarrhea, irritability, edema, and weakness. If your baby doesn’t receive early treatment, he may suffer from physical and mental retardation. He may also suffer from learning difficulties and neurological problems. Learning difficulties include speech, language, reading, and motor skills, and neurological symptoms include ataxia, dysmetria, and tremors. The girls may complain of ovarian impairment and high levels of FSH and gonadotropin hormones. High levels of hormones cause premature ovarian insufficiency and delayed puberty.
The baby should take galactose-free milk to avoid the complications of galactosemia. These complications include liver failure, kidney damage, brain damage, and cataract. Also, it may lead to shock or sepsis in late cases. Doctors can diagnose galactosemia through a blood test that detects the deficiency of the GALT enzyme. Also, the doctors use a genetic test to detect mutated genes in the baby and parents. Doctors can diagnose about 100% of infants through the neonates screening program in which doctors take a blood sample from the heel of an infant.
A galactose-free diet is the more curative therapy of galactosemia. So, the infant shouldn’t intake human milk because it contains galactose. You can feed this child a galactose-free milk formula. The baby with speech difficulties should have speech therapy as early as we can. At school age, the child needs an educational plan and learning some skills, which are necessary for some children with galactosemia according to mental development degree. Girls with galactosemia may need hormone replacement due to loss of the menstrual period.
Now, let’s see this disease in more detail. We will discuss the following:
- What causes galactosemia, and who is at risk of having it?
- What are its symptoms, signs, and complications?
- How will your child’s doctor diagnose if your child has this disease and confirm this diagnosis?
- How can the doctor treat your child, and what are the treatment options that he has?
Causes of galactosemia
Three types of genes are responsible for galactose metabolism. So, mutations of these genes (GALE, GALK1, and GALT) cause galactosemia. The mutated GALT causes classic galactosemia, which is the most serious and common. Classic galactosemia causes complete failure of galactose metabolism. Also, GALT mutation can cause variant Duarte galactosemia, which decreases galactose metabolism by 75%. Variant Duarte galactosemia isn’t dangerous and doesn’t need treatment because there is no complete failure. GALK1 mutation causes type II galactosemia, while GALE mutation causes type III galactosemia. Type II and type III are severe and rare forms, and they have a mild presentation. So, when we say galactosemia, we mean classic galactosemia.
Infants at risk of having galactosemia
The baby becomes at risk of galactosemia if both parents are carriers of the mutated gene. Galactosemia is an autosomal recessive disease, so the child should receive two copies of the mutated gene from both parents. If the two parents are carriers, the chance to get a baby with galactosemia is 25%, while 50% are carriers and 25% are healthy. The risk of galactosemia is equal in males and females.