Review of the N314D Point Mutation on the GALT Gene and its Relationship to Galactosemia Type I - Term Paper Example

The UDP- galactose, found in the liver and erythrocytes, is required for the major cell functions like chemical signaling, building cellular structures, transporting molecules and producing energy. Since, galactose-1-phosphate is toxic to the parenchymal cells present prominently in liver, kidney and brain, accumulation of it in those organs leads to severe damage to them. According to Fleisher (2012), this disease severely attacks 20% of the patients at the infant stage itself, and so Galactosemia type I is screened when an individual is still in their infancy.

The procedure, which utilizes dried blood on filter paper, screens for galactosemia by performing analysis on the total galactose (galactose and galactose-1-phosphate), as well as the activity of the GALT enzyme itself. While effective, false positives frequently occur due to environmental factors and the high frequency of the Duarte-D2 mutation (N314D). (Carney et al., 2009). Environmental factors such as heat and humidity, as well as sample handling procedures, may affect the GALT assay providing for low activity and false positive results.

The variation in the results may be even due to the sample handling procedures. Infants die within a few days on exposure to milk, as lactose sugar present in the milk gets converted into galactose and this galactose accumulates in the infants. The accumulation of galactose-1-phosphate may lead to cirrhosis, cataract and severe mental retardation. Infants with this disease will have hemolysis, albuminaria and elevated clotting times, with hepatomegaly being the common cause. (Fleisher, 2012).

If undiagnosed, or left untreated, the mortality rate in infants is nearly 75% (Elsas et al., 1994). Additionally, even with a properly controlled, galactose-free diet, adults with galactosemia typically develop symptoms as they grow older, some of these symptoms include learning