Galactosaemia in is a rare, inherited genetic disease where your body is o unable to break down galactose sugars, found in milk and all products containing milk. Accumulation of galactose sugars causes damage to tissues and organs. This can cause life-threatening signs and symptoms. Type l Galactosaemia (or Classic Galactosaemia), which is the most common and severe form of Galactosaemia, is found in 1 in 30,000 to 60,000 newborns. Type II Galactosaemia is found in 1 in 100,000 newborns and Type lll is the rarest form. Galactosaemia is most common in people from Ireland where 1 in 24,000 newborns are diagnosed with Galactosaemia especially those who are descendants from Irish Travellers.
The signs and symptoms of Galactosaemia differ depending on each person (as does the severity) but, the most common among babies are convulsions (violet, irregular movement of the body caused by involuntary contracting of the muscles), irritability, lethargy (lack of energy), poor feeding, poor weight gain, vomiting, bacterial infections, yellowing of the skin and cataracts forming in the eyes (as seen in figure 1). In older children, adolescents and adults learning difficulties, speech development delay, cataracts in eyes and ovarian failure in girls are the common.
Figure 1. Signs and Symptoms of Galactosaemia. N/A. (2016) Metabolic Disorders Inborn Errors of Metabolism. Retrieved from http://slideplayer.com/slide/4909551/
Galactosaemia is an inherited, autosomal, recessive disorder. This means that both parents must be carriers of the mutated gene, and each of their children has a 25% chance of bing diagnosed with Galactosaemia ( as seen in figure 2). The dominant gene cannot be present in the persons genotype for them to be diagnosed as Galactosemic.
Figure 2. Pedigree of Autosomal Recessive Inheritance. N/A. What is Galactosaemia? Retrieved from http://www.agsn.org.au/what-is-galactosaemia/
Galactosaemia is caused by a mutilation in a particular gene that effects the different enzymes involved in breaking down galactose sugars into glucose and other energy storing molecules. The three types of Galactosaemia all have different types of genes that are effected. The mutation (non working gene) in Type l Galactosaemia is located in the GALT gene at chromosome 9, position 13.3 (as seen in figure 3). Type ll is located in the GALK1 gene at chromosome 17 position 25.1 (as seen in figure 4). Type lll is a mutation located in the GALE gene at chromosome 1, position 36.11 (as seen in figure 5).
Figure 3. GALE gene mutation. N/A. (2017) GALE Gene - Genetics Home Reference. Retrieved from https://ghr.nlm.nih.gov/gene/GALE#location
Figure 4. GALK1 gene mutation. N/A. (2017) GALK1 Gene - Genetics Home Reference. Retrieved from https://ghr.nlm.nih.gov/gene/GALK1#location
Figure 5. GALT gene mutation. N/A. (2017) GALT Gene - Genetics Home Reference. Retrieved from https://ghr.nlm.nih.gov/gene/GALT#location
Galactosaemia can be detected before birth by collecting a sample of fluid from the mothers amniotic sac (bag of fluid inside a woman womb were the unborn baby develops and grows). When the baby is born a heel prick test, where blood is drawn from a vein, or a urine test can be used to determine whether or not the person is Galactosemic. However, a blood test is more reliable then a urine sample.
Unfortunately there is no cure for Galactosaemia however, a galactose free diet significantly reduces life-threatening symptoms from effecting the patient. When the galactose free diet is initiated after the birth of the child and maintained during the first three years, symptoms can be avoided and a tolerance to galactose sugars can build up slightly. Those who have Galactosaemia have a normal lifespan if they follow the galactose free diet plan, but if the diet is not consistent irreversible mental problems and severe damage to your body can occur. Those with Galactosaemia also have regular blood test so doctors can monitor their galactose levels and calcium supplements need to be taken to avoid calcium deficiency. A professional nutritionist is also needed to help with the galactose free diet plan.
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