What is Galactosaemia?
Galactose in the blood
Galactosaemia is a genetic condition that affects the body’s ability to process galactose. Galactose is a naturally occurring sugar found in a number of human organs and other living things. It is also a part of lactose, the main sugar found in animal milks.
The literal meaning of galactosaemia is “galactose in the blood”. This is because of the fact that since the body cannot breakdown galactose the body retains high levels of galactose in the blood.
The reason why classic galactosaemics cannot process galactose is because they lack the enzyme called galactose-1-phosphate uridyl transferase (commonly referred to as GALT). There are two other less common types of galactosaemia, being galactokinase deficiency and galactose epimerase deficiency, where the body lacks other enzymes used in the breakdown of galactose.
Galactosaemia is different from lactose intolerance or milk allergy. The diet for galactosaemia is, therefore, also different as there are some foods that are high in galactose but do not contain milk or lactose.
Please click here for more details on the diet for galactosaemia.
Diagnosis and treatment
At present there is no cure for galactosaemia and the main treatment is a low galactose diet. This treatment has been found to be very successful with infants and has significantly reduced some of the common problems that previously had severe consequences for newborns. In most Australian States galactosaemia is tested for as part of the Guthrie (or heel prick) test performed a few days after birth. However, galactosaemia is not a standard part of the Guthrie test in all States and persons with an increased risk of having a child with galactosaemia should discuss newborn testing with their medical team.
The symptoms of galactosaemia are different for newborns and older galactosaemics.
Common symptoms in newborns include:
- severe jaundice
- bacterial infections
- difficulty gaining weight
- difficulty feeding
- small cataracts
The bacterial infections can be severe and prior to the introduction of early testing for galactosaemia the mortality rate for babies born with galactosaemia was high. However, early diagnosis and the associated transition to soy formula has had a significant impact and the prognosis for babies diagnosed early is now very good.
Common symptoms in older children, adolescents and adults include:
- learning difficulties
- speech developmental delays
- ovarian failure in girls
- cataracts (in particular of those with galactokinase deficiency)
An unusual feature of galactosaemia is that the symptoms are not uniform and some galactosaemics will show very few (if any) symptoms, while others will show a number of symptoms. Studies have also failed to show a clear link between a patient’s galactose levels and the number and severity of the symptoms suffered. This is different to other metabolic conditions (such as PKU), which show a clear link between diet management and prognosis.
Please refer to the ASIEM Galactosaemia handbook via the link below for more detailed information: https://www.hgsa.org.au/documents/item/50