GALT deficiency means: Galactosemia is a condition that prevents people from metabolizing simple sugars galactose. Half of lactose, which is the sugar found in milk, comes from galactose. Because lactose, which is composed of galactose, glucose and sugar, is bound together, it is called a diaccharide. Galactose can build up in infants with galactosemia if they are given milk. This could cause damage to their liver, kidneys, and eyes. Galactosemia patients cannot tolerate milk, human or non-human, or any galactose-containing food. Milk products can cause liver damage, mental retardation and cataract formation.
(in Medical Dictionary)

What else does GALT deficiency mean?

A lack of activity in GALT is often a sign of an illness. Direct measurement of this enzyme is possible for prenatal diagnosis.
(in Medical Dictionary)

Galactosemia symptoms include yellowish skin discoloration and vomiting. You may also notice hepatomegaly an enlarged liver, hypoglycemia, low blood sugar and aminoaciduria amino aciduria. These symptoms can be seen in urine, kidney disease, cysts, mental retardation, cirrhosis, fluid collection from the abdomen, cataracts, ascites, and cirrhosis.
(in Medical Dictionary)

Galactosemia is a condition in which a newborn baby with the disease develops jaundice and vomiting. A enlarged liver and low blood sugar could mean that the body is more susceptible to infection. The infant may become cirrhosis-prone if they continue to be fed milk products. This can lead to cataract formation and partial blindness.
(in Medical Dictionary)

It is important for parents to educate their child about the dangers of milk, milk products and dry milk products. It is important to be a knowledgeable consumer and read all product labels. A normal life expectancy is possible if the diagnosis is done early. Mild intellectual impairment can still occur despite strict avoidance.
(in Medical Dictionary)

After the diagnosis is made, it’s important to avoid all dairy products and any milk-containing products. You can feed your infant soy, meat-base, Nutramigen, a milk-free protein hydrolysate, or any other formula that is lactose free. This condition can last a lifetime and the infant must abstain from all milk and dairy products.
(in Medical Dictionary)

Galactosemia can be inherited from an autosomal recessive gene. GALT deficiency clasic galactosemia is one form of this disease. Galactose Kinase deficiency the other. GALT deficiency, which is the more severe of the two forms, is the worst. GALT is located on chromosome 9p13.
(in Medical Dictionary)