A Metabolic Disorder: Galactomsemia

A 1908 publication entitled, “Sugar Excretion in Infancy” described a breast-fed infant with liver and spleen enlargement, failure to grow, and “galactosuria.” The infant later died and an autopsy revealed cirrhosis of the liver. It is believed that this publication by Von Reuss was the first description of an individual with the condition called galactosemia.

Galactosemia is a rare disorder of carbohydrate metabolism in which the person’s ability to convert the simple sugar, galactose, into glucose is impaired. Galactose is a component of lactose which is a more complex sugar commonly found in milk products. Because the individual is unable to metabolize galactose, toxic levels of the compound build up in the cells.

Galactosemia is an autosomal recessive condition in which the affected individual inherits one defective gene from each parent. This gene defect inhibits the normal production and function of the GALT enzyme which is needed to properly metabolize galactose. Two variants of the gene for galactosemia have been identified. One mutation results in a milder version of the disorder, while the other is responsible for a more severe form.

Infants with galactosemia are usually normal at birth, but will soon develop gastrointestinal problems, jaundice, and vomiting. If not detected and diagnosed early, this metabolic condition can result in liver disease, cataract formation, mental retardations, and life-threatening bacterial infections. It is estimated that one in every 40 individuals is a carrier of this defect and that the incidence for the disease is 1 in 60,000. As these children age, it is not unusual to see central nervous system difficulties including speech delay, motor skills delay, and specific learning disabilities. Females with galactosemia may also experience ovarian failure or dysfunction.

Treatment for this condition is galactose and lactose restriction for life. The person with galactosemia will never be able to properly metabolize galactose. Currently there is no chemical or enzyme replacement available for treatment. However, children who are diagnosed early through newborn screening have excellent long-term opportunities for development.

Additional information on this condition may be found on the following web sites: www.galactosemia.org and www.savebabies.org.