What gene is galactosemia located on?
The gene encoding galactose-1-phosphate uridyltransferase (GALT) is located in chromosome 9 (9p13). Galactosemia, caused primarily by GALT deficiency, is an autosomal recessive inborn error of metabolism that has been associated with greater than 100 different mutant genotypes (149).
How is galactosemia passed genetically?
Galactosemia is an inherited disorder. This means it is passed down through families. If both parents carry a nonworking copy of the gene that can cause galactosemia, each of their children has a 25% (1 in 4) chance of being affected with it.
What is the genotype of galactosemia?
Several disease-causing mutations are common in patients with classic galactosemia (G/G genotype). The most frequently observed is the Q188R classic mutation. This mutation accounts for 60% to 70% of classical galactosemia alleles.
What is the GALT gene?
The GALT gene provides instructions for making an enzyme called galactose-1-phosphate uridylyltransferase. This enzyme enables the body to process a simple sugar called galactose, which is present in small amounts in many foods.
Is there galactose in breast milk?
Babies with galactosemia (geh-lak-teh-SEE-mee-uh) have high levels of galactose in their blood. Lactose is the main type of sugar in milk, milk-based formulas, and breast milk. Lactose is made up of glucose and galactose.
Is galactosemia dominant or recessive?
Galactosemia is an autosomal recessive genetic disorder. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent.
What type of mutation is galactosemia?
Mutations in the GALT gene cause classic galactosemia (type I). Most of these genetic changes almost completely eliminate the activity of the enzyme produced from the GALT gene, preventing the normal processing of galactose and resulting in the life-threatening signs and symptoms of this disorder.
How common is it to be a carrier of galactosemia?
Carriers do not have galactosemia because the other GALT gene is working correctly. When both parents are carriers, there is a 25% chance in each pregnancy for the child to have galactosemia. There is a 50% chance for the child to be a carrier, just like the parents.
Does breast milk have galactose?
How do I know if my child has galactosemia?
Symptoms start to show up within a few days after they begin to drink breast milk or formula with lactose — the milk sugar that contains galactose. Your baby first loses their appetite and starts vomiting. Then they get jaundice, a yellowing of the skin and the whites of their eyes. Diarrhea is common, too.
How common is Duarte galactosemia?
Duarte variant galactosemia is detected in as many as 1:3,500 screened births in some states and essentially zero in others, largely reflecting differences in NBS protocols [Pyhtila et al 2015] (see Diagnosis, Erythrocyte GALT enzyme activity).
Does galactosemia run in families?
To have galactosemia, a child must inherit two galactosemia genes, one from each parent. In galactosemia, galactose and its byproducts build up in the blood. This can damage cells and parts of the body.