Galactosemia is a rare genetic metabolic disorder (autosomal recessive mode of inheritance), that affects ability to metabolize the sugar galactose into glucose. Galactose makes up half of lactose, the sugar found in milk. The other sugar is glucose. Glucose is readily usable by the body but galactose needs an enzyme called

GALT to turn it into a sugar that the body can use. In nearly all people with this condition the body lacks the enzyme that is used in this process. If an infant with galactosemia is given milk, substances made from galactose build up in the infant's system. These substances damage the liver, brain, kidneys, and eyes.
Persons with galactosemia cannot tolerate any form of milk (human or animal). They must be careful about eating other foods containing galactose.

The carriers of the disorder will not get sick. But when two carriers have a child together there is a 1 in 4 chance (25%) the child will have galactosemia, a 2 in 4 chance (50%) the child will be a carrier of the disease, and a 1 in 4 chance (25%) the child will not be a carrier or have the disease. These are the chances with each birth. If one child in a family is diagnosed with Galactosemia then all children born before and/or after should also be tested. During pregnancy an amniocentesis test may detect if the infant has Galactosemia
Its incidence is about 1 per 40.000 to 60.000 births among Caucasians. The rate is different for other groups. It is much rarer in Japan and much more common in Italy. Galactosemia is also very common within the Irish population.

Infants affected by galactosemia typically present with symptoms of lethargy, vomiting, diarrhea, failure to thrive, and jaundice. None of these symptoms are specific to galactosemia, often leading to diagnostic delays.
Signs include:
• Amino acids in the urine and/or blood plasma (aminoaciduria)
• Enlarged liver (hepatomegaly)
• Fluid in the abdomen (ascites)
• Low blood sugar (hypoglycemia)
A galactosemia test is a blood test (from the heel of the infant) or urine test that checks for three enzymes that are needed to change galactose sugar that is found in milk and milk products-into glucose, a sugar that your body uses for energy. A person with galactosemia doesn't have one of these enzymes. This causes high levels of galactose in the blood or urine.

There are three forms of the disease:
• GALT 9p13 Galactose-1 phosphate uridyl transferase deficiency (classic galactosemia, the most common and most severe form)
• GALK1 17q24 galactokinase (galactokinase deficiency)
• GALE 1p36-p35 UDP galactose epimerase (galactose epimerase deficiency)
Galactosemia is normally first detected through newborn screening. Affected children can have serious, irreversible effects or even die within days from birth. It is important that newborns be screened for metabolic disorders without delay. Galactosemia can even be detected before any ingestion of galactose-containing formula or breast milk.

Tests include:
• Blood culture for bacteria infection (E. coli sepsis).
• Enzyme activity in the red blood cells.
• Ketones in the urine.
• Prenatal diagnosis by directly measuring the enzyme galactose-1-phosphate uridyl transferase.
• "Reducing substances" in the infant's urine, and normal or low blood sugar while the infant is being fed breast milk or a formula containing lactose.
Detection of the disorder through newborn screening (NBS) does not depend on protein or lactose ingestion, and, therefore, it should be identified on the first specimen unless the infant has been transfused. A specimen should be taken prior to transfusion. The enzyme is prone to damage if the sample is delayed in the mail or exposed to high temperatures. The routine NBS is accurate for detection of galactosemia. Two screening tests are used to screen infants affected with galactosemia - the Beutler's test and the Hill test. In fact a third test, called the "Florida test", is also normally performed on all galactosemia positives. The Beutler's test screens for galactosemia by detecting the level of enzyme of the infant. Therefore, the ingestion of formula or breast milk does not affect the outcome of this part of the NBS, and the NBS is accurate for detecting galactosemia prior to any ingestion of galactose.
Galactosemia is sometimes confused with lactose intolerance, but galactosemia is a more serious condition. Lactose intolerant individuals have an acquired or inherited shortage of the enzyme lactase, and experience abdominal pains after ingesting dairy products, but no long-term effects. In contrast, a galactosemic individual who consumes galactose can cause permanent damage to their bodies.

The only treatment for classic galactosemia is very strict diet (eliminating lactose and galactose from the diet).
Infants can be fed with:
• Soy formula
• Meat-based formula or Nutramigen (a protein hydrolysate formula)
• Another lactose-free formula
Calcium supplements are recommended.
Even with an early diagnosis and a restricted diet, however, some individuals with galactosemia experience long-term complications such as speech difficulties, learning disabilities, neurological impairment (e.g. tremors, etc), and in girls, ovarian failure. These complications are treated if they appear in a manner similar to the way they would be treated in a non-galactosemic. Such complications have not been associated with Duarte galactosemia, and many individuals with Duarte galactosemia do not need to restrict their diet at all. Infants with classic galactosemia cannot be breast-fed due to lactose in human breast milk and are usually fed a soy-based formula.
Long term complication of galactosemia includes:
• Speech deficits.
• Delayed speech development.
• Tremors and uncontrollable motor functions (ataxia).
• Dysmetria.
• Diminished bone density.
• Premature ovarian failure.
• Cirrhosis of the liver.
• Irregular menstrual periods and ovarian failure (means that the ovaries, where the eggs for having babies come from, either do not develop before she is born or they won't work as she grows up.
• Mental retardation.
• Severe infection with bacteria (E. coli sepsis).
• Hemorrhage of the gel-like substance of the eye.
• Cataract.
• Death (if there is galactose in the diet).

Galactosemia is different for each child and will not cause the same problems with all children. Even when all instructions are followed, some children do not do as well as others. Studies tell us that children who were not given the strict diet have an increased risk of having one or more of the problems listed above.

It is helpful to know your family history. If you have a family history of galactosemia and want to have children, genetic counseling will help you make decisions about pregnancy and prenatal testing. Once the diagnosis of galactosemia is made, genetic counseling is recommended for other members of the family.