Galactosemia

Galactosemia - What is Galactosemia?

Galactosemia (Galactosaemia) is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly.

Galactosemia is not related to and should not be confused with lactose intolerance. Galactosemia follows an autosomal recessive mode of inheritance that confers a deficiency in an enzyme responsible for adequate galactose degradation.

Goppert first described the disease in 1917, with its cause as a defect in galactose metabolism being identified by a group led by Herman Kalckar in 1956.

Its incidence is about 1 per 60,000 births. It is much rarer in Japan and much more common in Italy, specifically the traveler region. Galactosemia is also very common within the Irish Traveller population. This is attributed to consanguinity within a relatively small gene pool.

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Galactosemia Causes

Lactose in food (such as dairy products) is broken down by the enzyme lactase into glucose and galactose.

In individuals with galactosemia, the enzymes needed for further metabolism of galactose are severely diminished or missing entirely, leading to toxic levels of galactose in the blood, resulting in hepatomegaly (an enlarged liver), cirrhosis, renal failure, cataracts, brain damage, and ovarian failure.

Without treatment, mortality in infants with galactosemia is about 75%.

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Galactosemia" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Galactosemia Diagnosis

Infants are now routinely screened for galactosemia in the United States, and the diagnosis is made while the person is still an infant.

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.

Luckily, most infants are diagnosed on newborn screening.

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.

Galactosemia is normally first detected through newborn screening, or NBS. 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 through NBS before any ingestion of galactose-containing formula or breast milk.

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 effect the outcome of this part of the NBS, and the NBS is accurate for detecting galactosemia prior to any ingestion of galactose.

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Galactosemia" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.

Galactosemia Treatments

The only treatment for classic galactosemia is eliminating lactose and galactose from the diet.

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), symptoms 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.

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.

Long term complication of galactosemia includes:

  • Speech deficits
  • Ataxia
  • Dysmetria
  • Diminished bone density
  • Premature ovarian failure
  • Cataract

This article is licensed under the Creative Commons Attribution-ShareAlike License. It uses material from the Wikipedia article on "Galactosemia" All material adapted used from Wikipedia is available under the terms of the Creative Commons Attribution-ShareAlike License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.