Pediatric Pearls. 7 Facts about Galactosemia

September 5, 2023

The last Pediatric Pearl post reviewed the basics of the newborn metabolic screen. Let’s look at several of the disorders that are screened for, starting with galactosemia.

The pearls I remember about galactosemia are: autosomal recessive, act fast, poor eating and vomiting, early cataracts and E Coli infections.

#1 What is galactosemia?

Galactosemia is a genetic metabolic disorder in which infants are born without the ability to convert galactose into glucose. Glucose is the form of sugar used by the body for energy.

There are three main types of galactosemia:

• Classic (Type I)

• Galactokinase deficiency (Type II)

• Galactose epimerase deficiency (Type III)

This post will discuss classic galactosemia which occurs when an enzyme called galactose-1-phosphate uridyltransferase (GALT) is missing or not functional. This liver enzyme is responsible for breaking down galactose into glucose. When galactose cannot be changed to glucose, it, as well as its byproducts such as galactose-1-phosphate, builds up in tissues and blood and affects many parts of the body.

#2 Galactosemia is an autosomal recessive disease. What does that mean?

Galactosemia is passed from parent to child as an autosomal recessive disease. This means that a child needs to inherit two copies of the defective gene (one from each parent) in order to have the disease.