This report describes general characteristics of the group of diseases classified as galactosemias. Galactosemia is a genetically heterogeneous disorder, with multiple genes and mapped loci. A listing of galactosemia subtypes can be found in the table below, with links to more detailed reports for subtypes that have been investigated using fly models.
[updated Jul. 2020 by FlyBase; FBrf0222196]
Classic galactosemia (type I) is the most severe and the most common form of the condition, occurring in 1 in 30,000-60,000 newborns. If infants with classic galactosemia are not treated promptly with a low-galactose diet, life-threatening complications appear within a few days after birth. Affected infants typically develop feeding difficulties, lethargy, failure to thrive, jaundice, liver damage, and abnormal bleeding. Galactosemia type II and type III are less common and are typically less severe. [from Genetics Home Reference, Galactosemia; 2016.01.25]
Galactosemias are disorders of galactose metabolism. Symptoms vary, depending upon the enzyme affected. [from MIM:230400, MIM:230200. MIM:230350, MIM:618881; 2020.07.13]
Mutations in the GALT, GALK1, GALE, and GALM genes cause galactosemia; in each case the disease is inherited as an autosomal recessive. [from MIM:230400, MIM:230200. MIM:230350, MIM:618881; 2020.07.13]
Galactose is not required for normal development; the symptoms of galactosemia are due to the toxic build-up of galactose and related compounds, resulting in damage to multiple tissues and organs. [Genetics Home Reference, Galactosemia; 2016.01.28]
Galactose is one of the two simple sugars that comprise lactose, the sugar found in milk.
