The word galactosaemia means “galactose in the blood”. It is a hereditary condition preventing the body from digesting galactose due to lack of enzymes used to breakdown galactose, leading to toxic accumulation of galactose in the blood.
There are three different types of galactosaemia. The most common and the most severe form of the condition is “classic galactosaemia”, where the body lacks an enzyme called galactose-1-phosphate uridyl transferase (GALT). It occurs in around 1 in 50,000 babies born in Australia and New Zealand.
What is galactose?
Along with glucose and fructose, galactose is a simple sugar, also called monosaccharide. When two monosaccharaides join together chemically they form double sugar called disaccharide.
Galactose combined with glucose creates lactose, the milk sugar.
Thus the major dietary source of galactose is milk and milk products. Some fruit and vegetables, legumes, and fermented foods also contain galactose. Medications, particularly tablets and capsules, often contain lactose too.
The ‘Australian Galactosaemia Support Network’ provides the following list of foods that should be strictly avoided by people with galactosaemia:
- All animal milks (human breast milk, cow’s milk, goats milk) Please note: some hard mature cheeses are allowed.
- Lactose free products (lactose free milk, cream, yoghurt and custard still contain galactose)
- Chickpeas (besan flour, chickpea dahl, hummus, falafel)
- Legumes (dried peas, beans, lentils)
- Fermented soybean products (miso, tempeh, natto, soy sauce)
- Offal meat (liver, kidney, brains, pate)
Symptoms of galactosaemia
Galactosaemia is a life-threatening disorder. Within the first few weeks of life, untreated infants manifest feeding problems, poor weight gain, vomiting, diarrhoea, jaundice, bleeding due to abnormal clotting, liver failure, lethargy, and bacterial infections.
If the condition is diagnosed and treated during the first three to ten days of life, the symptoms resolve quickly and prognosis is good. However, delayed treatment can lead to further complications. Older children, adolescents and adults may show learning and speech problems, mental retardation, poor motor function, cataracts, short stature, and premature ovarian failure in females.
How is galactosaemia diagnosed?
In Australia, all newborns undergo screening tests as part of normal newborn care. The test is carried out on a blood sample obtained by heel prick, usually done within a few days of birth.
Treatment of galactosaemia
Currently the only treatment for galactosaemia is immediate and lifelong galactose elimination from the diet. However, even with the appropriate diet, most patients suffer at least 1-2 long-term chronic complications, such as low IQ, poor coordination and balance, as well as memory, speech, and language problems. Treatment for complications of galactosaemia varies and may include cataract surgery, speech therapy, occupational therapy, and infertility treatment for women with premature ovarian insufficiency.
Bone health
Galactosaemia patients are at risk of calcium deficiency since they cannot consume dairy products. They have been found to have lower bone mass when compared to the general population and may need supplementation of bone minerals and vitamins such as calcium, vitamin K, and vitamin D.
Galactosaemia vs. lactose intolerance
Galactosaemia and lactose intolerance are two very different conditions and must not be confused. Lactose intolerance is more common than galactosaemia and is not considered a serious life long condition. People who are lactose intolerant are unable to digest lactose due to a deficiency of the enzyme lactase. The condition results in digestive symptoms such as abdominal pain, flatulence, bloating and diarrhoea, without any serious long-term complications. Many people diagnosed with lactose intolerance can tolerate small amounts of lactose without symptoms developing. Lactase enzyme is also available in the form of tablets and caplets that can be taken orally immediately before consuming dairy, so it can be digested without any symptoms.
Dean’s Story
Dean was born in 1953 in Canada. Although galactosaemia was recognised and described early in the century, the actual defective gene that caused it was not found until 1956, and even then doctors knew very little about it.
Within a day of being breast fed Dean fell very ill. His doctors, thinking he was reacting to his mother’s breast milk, switched him to regular baby formula, which was based on cow’s milk. Shortly after consuming the baby formula Dean became even sicker and fell into a coma. Doctors were baffled by his condition.
Frantic telephone calls were made to other specialists and the medical literature was thoroughly searched, eventually reaching the correct diagnosis.
When Dean came out of coma he was put on a dairy-free formula. His symptoms seemed to resolve very quickly and he was released from hospital. However, around the age of 2 his mother noticed some developmental delays. Further tests revealed brain damage, probably as a result of his delayed diagnosis. Growing up, Dean attended a special school, and always seemed to suffer from poor balance and a tremor that got worse over the years, eventually confining him to a wheel chair. Sadly, Dean passed away at age 54, and is considered one of the longest living galactosaemia patients for his time.
At present, only two out of ten Canadian provinces offer universal newborn screening for galactosaemia.
References
- Australian Galactosaemia Support Network. Available at: http://www.agsn.org.au/what-is-galactosaemia/
- Berry, G. 2015. Galactose-1-Phosphate Uridyltransferase Deficiency (Galactosemia). Available at: https://emedicine.medscape.com/article/944069-overview
- Coelho, A.I. et al., 2017. Sweet and sour: an update on classic galactosemia. Journal of inherited metabolic disease, 40(3), pp.325–342. Available at: http://www.ncbi.nlm.nih.gov/pubmed/28281081
- NSW and ACT Newborn Screening Programme 2015. Sampling Information and Guidelines To be used in conjunction with the 2015 NSW Ministry of Health Policy Directive, compliance of which is mandatory. Available at: https://www.schn.health.nsw.gov.au/files/attachments/newborn_screening_guidlines_2015.pdf
- U.S National Library of Medicine 2018. Galactosemia. Available at: https://ghr.nlm.nih.gov/condition/galactosemia#genes
- van Erven, B. et al., 2017. Bone Health in Classic Galactosemia: Systematic Review and Meta-Analysis. JIMD reports, 35, pp.87–96. Available at: http://www.ncbi.nlm.nih.gov/pubmed/27995581
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