Classic Galactosemia

Galactosemias are disorders of carbohydrate metabolism caused by a deficiency of one of three enzymes involved in galactose metabolism (galactose-1-phosphate uridyltransferase [GALT], galactokinase [GALK], or uridine diphosphate galactose-4'-epimerase [GALE]).  Classic galactosemia, caused by a deficiency in GALT due to GALT gene variants, is the most common and most severe form and can lead to liver disease, sepsis, or death if not diagnosed and treated soon after birth.  Newborn screening for classic galactosemia, which affects approximately one in 53,500 neonates in the United States, has been established in all 50 states.  Early diet-based interventions can prevent neonatal complications and irreversible end-organ damage, but even with such interventions, long-term effects such as infertility and neurologic complications may occur.   Although not all forms of galactosemia require treatment, classic galactosemia requires early and lifelong lactose and galactose restriction.   Diagnosis is based on testing for GALT enzyme activity, which is absent or nearly undetectable in patients with the disorder, and often involves DNA analysis of the GALT gene to determine if pathogenic variants are present.  Other forms of galactosemia include type II and III, which are caused by GALK and GALE deficiencies, respectively. 

Tabs Content
Content Review: 
December 2018

Last Update: November 2019